Updated CC API docs for delete service endpoint to include purge parameter

[#63185416]
Support updating uaa clients per [#62008174]
Move in_test_mode? presentation concerns to ErrorPresenter.

- previously this logic was in vcap.rb
- now ErrorPresenter determines when to present sanitized or unsanitized
  error information based on test_mode
- remove in_test_mode? stubbing from all specs
- moved service_binding model test out of controller spec and properly
  onto service_binding_spec
Add dashboard sso client updating to broker_api_v2.2_spec.rb

[#62008174]
SSO update now does a delete and recreate of the SSO client. [#62008174]