Flaky test failures in community_program_renew_purchase_spec.rb

### Problem

I frequently seen the `rspec-zuora` job fail because of one test failure in `spec/features/subscriptions/community_program_renew_purchase_spec.rb`.  Typically, the job passes on retry, but it's an inconvenience, especially when it requires a merge train retry by a maintainer.  It also wastes pipeline resources and ultimately increases costs.  For reference, this spec was introduced in https://gitlab.com/gitlab-org/customers-gitlab-com/-/merge_requests/4633+.

I went through a few pages of [pipelines](https://gitlab.com/gitlab-org/customers-gitlab-com/-/pipelines) and quickly found a number of failures because of this spec.

Examples of job failures:
- https://gitlab.com/gitlab-org/customers-gitlab-com/-/jobs/3784238665
- https://gitlab.com/gitlab-org/customers-gitlab-com/-/jobs/3782904859
- https://gitlab.com/gitlab-org/customers-gitlab-com/-/jobs/3782569469
- https://gitlab.com/gitlab-org/customers-gitlab-com/-/jobs/3779860534

<details><summary>Click to expand</summary>

```
  1) Community Program - Renewals when accessing community program landing page when customer has a self-managed subscription successfully renews subscription
     Failure/Error: ::IronBank.client.connection.post(url, *args)
     VCR::Errors::UnhandledHTTPRequestError:
       ================================================================================
       An HTTP request has been made that VCR does not know how to handle:
         POST https://rest.apisandbox.zuora.com/v1/orders/preview
       VCR is currently using the following cassette:
         - /builds/gitlab-org/customers-gitlab-com/spec/fixtures/vcr_cassettes/community_program_-_renewals/when_accessing_community_program_landing_page/when_customer_has_a_self-managed_subscription/successfully_renews_subscription.yml
           - :record => :none
           - :match_requests_on => [:zuora]
       Under the current configuration VCR can not find a suitable HTTP interaction
       to replay and is prevented from recording new requests. There are a few ways
       you can deal with this:
         * If you're surprised VCR is raising this error
           and want insight about how VCR attempted to handle the request,
           you can use the debug_logger configuration option to log more details [1].
         * You can use the :new_episodes record mode to allow VCR to
           record this new request to the existing cassette [2].
         * If you want VCR to ignore this request (and others like it), you can
           set an `ignore_request` callback [3].
         * The current record mode (:none) does not allow requests to be recorded. You
           can temporarily change the record mode to :once, delete the cassette file 
           and re-run your tests to allow the cassette to be recorded with this request [4].
         * The cassette contains 42 HTTP interactions that have not been
           played back. If your request is non-deterministic, you may need to
           change your :match_requests_on cassette option to be more lenient
           or use a custom request matcher to allow it to match [5].
       [1] https://www.relishapp.com/vcr/vcr/v/6-1-0/docs/configuration/debug-logging
       [2] https://www.relishapp.com/vcr/vcr/v/6-1-0/docs/record-modes/new-episodes
       [3] https://www.relishapp.com/vcr/vcr/v/6-1-0/docs/configuration/ignore-request
       [4] https://www.relishapp.com/vcr/vcr/v/6-1-0/docs/record-modes/none
       [5] https://www.relishapp.com/vcr/vcr/v/6-1-0/docs/request-matching
       ================================================================================
     Shared Example Group: "subscription renewal" called from ./spec/features/subscriptions/community_program_renew_purchase_spec.rb:59
     # ./spec/fixtures/vcr_cassettes/community_program_-_renewals/when_accessing_community_program_landing_page/when_customer_has_a_self-managed_subscription/successfully_renews_subscription.yml <- from VCR cassette
     # ./lib/gitlab/iron_bank.rb:14:in `post'
     # ./lib/zuora/client/orders_preview.rb:16:in `create'
     # ./lib/zuora/client/orders_preview.rb:11:in `get'
     # ./app/jobs/zuora/orders/preview.rb:7:in `perform'
     # ./app/services/zuora/orders/preview_service.rb:20:in `execute'
     # ./app/services/zuora/orders/preview_service.rb:14:in `execute'
     # ./app/services/zuora/orders/order_manager_service.rb:38:in `preview_result'
     # ./app/services/zuora/orders/order_manager_service.rb:20:in `execute'
     # ./app/services/zuora/orders/order_manager_service.rb:16:in `execute'
     # ./app/services/zuora/orders/amendment_manager_service.rb:53:in `block in order_result'
     # ./lib/utils/strong_memoize.rb:27:in `strong_memoize'
     # ./app/services/zuora/orders/amendment_manager_service.rb:52:in `order_result'
     # ./app/services/zuora/orders/amendment_manager_service.rb:25:in `execute'
     # ./app/services/zuora/orders/amendment_manager_service.rb:10:in `execute'
     # ./app/services/self_service/subscriptions/update_service.rb:134:in `update_zuora_objects'
     # ./app/services/self_service/subscriptions/update_service.rb:46:in `execute'
     # ./app/controllers/subscriptions_controller.rb:88:in `update'
     # ./lib/middleware/maintenance.rb:28:in `call'
     # ./lib/middleware/health_check/health_check_responder.rb:14:in `call'
     # ------------------
     # --- Caused by: ---
     # Capybara::ExpectationNotMet:
     #   expected to find visible css "h2" with text "Subscription created successfully!" but there were no matches. Also found "GitLab for Education Program - Self-managed Ultimate", which matched the selector but not all filters. 
     #   ./spec/features/subscriptions/community_program_renew_purchase_spec.rb:41:in `block (4 levels) in <top (required)>'
```

```
  1) Community Program - Renewals when accessing community program landing page when customer has a self-managed subscription successfully renews subscription
     Failure/Error: ::IronBank.client.connection.post(url, *args)
     VCR::Errors::UnhandledHTTPRequestError:
       ================================================================================
       An HTTP request has been made that VCR does not know how to handle:
         POST https://rest.apisandbox.zuora.com/v1/orders/preview
       VCR is currently using the following cassette:
         - /builds/gitlab-org/customers-gitlab-com/spec/fixtures/vcr_cassettes/community_program_-_renewals/when_accessing_community_program_landing_page/when_customer_has_a_self-managed_subscription/successfully_renews_subscription.yml
           - :record => :none
           - :match_requests_on => [:zuora]
       Under the current configuration VCR can not find a suitable HTTP interaction
       to replay and is prevented from recording new requests. There are a few ways
       you can deal with this:
         * If you're surprised VCR is raising this error
           and want insight about how VCR attempted to handle the request,
           you can use the debug_logger configuration option to log more details [1].
         * You can use the :new_episodes record mode to allow VCR to
           record this new request to the existing cassette [2].
         * If you want VCR to ignore this request (and others like it), you can
           set an `ignore_request` callback [3].
         * The current record mode (:none) does not allow requests to be recorded. You
           can temporarily change the record mode to :once, delete the cassette file 
           and re-run your tests to allow the cassette to be recorded with this request [4].
         * The cassette contains 42 HTTP interactions that have not been
           played back. If your request is non-deterministic, you may need to
           change your :match_requests_on cassette option to be more lenient
           or use a custom request matcher to allow it to match [5].
       [1] https://www.relishapp.com/vcr/vcr/v/6-1-0/docs/configuration/debug-logging
       [2] https://www.relishapp.com/vcr/vcr/v/6-1-0/docs/record-modes/new-episodes
       [3] https://www.relishapp.com/vcr/vcr/v/6-1-0/docs/configuration/ignore-request
       [4] https://www.relishapp.com/vcr/vcr/v/6-1-0/docs/record-modes/none
       [5] https://www.relishapp.com/vcr/vcr/v/6-1-0/docs/request-matching
       ================================================================================
     Shared Example Group: "subscription renewal" called from ./spec/features/subscriptions/community_program_renew_purchase_spec.rb:59
     # ./spec/fixtures/vcr_cassettes/community_program_-_renewals/when_accessing_community_program_landing_page/when_customer_has_a_self-managed_subscription/successfully_renews_subscription.yml <- from VCR cassette
     # ./lib/gitlab/iron_bank.rb:14:in `post'
     # ./lib/zuora/client/orders_preview.rb:16:in `create'
     # ./lib/zuora/client/orders_preview.rb:11:in `get'
     # ./app/jobs/zuora/orders/preview.rb:7:in `perform'
     # ./app/services/zuora/orders/preview_service.rb:20:in `execute'
     # ./app/services/zuora/orders/preview_service.rb:14:in `execute'
     # ./app/services/zuora/orders/order_manager_service.rb:38:in `preview_result'
     # ./app/services/zuora/orders/order_manager_service.rb:20:in `execute'
     # ./app/services/zuora/orders/order_manager_service.rb:16:in `execute'
     # ./app/services/zuora/orders/amendment_manager_service.rb:53:in `block in order_result'
     # ./lib/utils/strong_memoize.rb:27:in `strong_memoize'
     # ./app/services/zuora/orders/amendment_manager_service.rb:52:in `order_result'
     # ./app/services/zuora/orders/amendment_manager_service.rb:25:in `execute'
     # ./app/services/zuora/orders/amendment_manager_service.rb:10:in `execute'
     # ./app/services/self_service/subscriptions/update_service.rb:134:in `update_zuora_objects'
     # ./app/services/self_service/subscriptions/update_service.rb:46:in `execute'
     # ./app/controllers/subscriptions_controller.rb:88:in `update'
     # ./lib/middleware/maintenance.rb:28:in `call'
     # ./lib/middleware/health_check/health_check_responder.rb:14:in `call'
     # ------------------
     # --- Caused by: ---
     # Capybara::ExpectationNotMet:
     #   expected to find visible css "h2" with text "Subscription created successfully!" but there were no matches. Also found "GitLab for Education Program - Self-managed Ultimate", which matched the selector but not all filters. 
     #   ./spec/features/subscriptions/community_program_renew_purchase_spec.rb:41:in `block (4 levels) in <top (required)>'
Finished in 5 minutes 30 seconds (files took 19.03 seconds to load)
945 examples, 1 failure
Failed examples:
rspec './spec/features/subscriptions/community_program_renew_purchase_spec.rb[1:1:1:1]' # Community Program - Renewals when accessing community program landing page when customer has a self-managed subscription successfully renews subscription
```

</details>

### Proposal

Let's figure out what is making this spec flaky and fix it. :pray:

Story points: 1.0