Issue:
fix: fixes to surface level mandate issues

## Type of Change
<!-- Put an `x` in the boxes that apply -->

- [x] Bugfix

## Description
This Bugfixes fixes the following issues.
1. mandate_id not being populated in response for verify call
2. verify case while making payment for a mandate_id
3. validating mandate checks like currency and single use
<!-- Describe your changes in detail -->


### Additional Changes

- [ ] This PR modifies the database schema
- [ ] This PR modifies application configuration/environment variables

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1. `config`
4. `crates/router/src/configs`
5. `loadtest/config`
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## Motivation and Context
This PR deals with surface level bugs, and some data inconsistencies.
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## How did you test it?
<img width="621" alt="Screenshot 2022-12-20 at 2 02 23 PM" src="https://user-images.githubusercontent.com/51093026/208620240-b1fc1bb2-2414-4050-9836-1b9e9ebda704.png">

<img width="867" alt="Screenshot 2022-12-20 at 2 10 16 PM" src="https://user-images.githubusercontent.com/51093026/208622052-d8fe4fe5-9745-49ff-9cf1-f46282e9ece0.png">

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## Checklist
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- [x] I formatted the code `cargo +nightly fmt`
- [x] I addressed lints thrown by `cargo clippy`
- [x] I reviewed submitted code


Resolution:
<think>
PR Context:
- Title: fix: fix mandate behaviour post merge
- Merged: 2022-12-22T19:46:50Z
- Files changed: 3 files
- Commits: 3 commits

Implementation approach:
## Type of Change
<!-- Put an `x` in the boxes that apply -->

- [x] Bugfix

## Description
This bug was fixed in #180 but because of the PR order it was reintroduced in #191 
<!-- Describe your changes in detail -->


### Additional Changes

- [ ] This PR modifies the database schema
- [ ] This PR modifies application configuration/environment variables

<!-- 
Provide links to the files with corresponding changes.

Following are the paths where you can find config files:
1. `
</think>

To implement this, you'll need to modify:


**Detailed Implementation:**


**Commit 1:** fix: fix mandate behaviour post merge (#221)
Files to modify:


**crates/router/src/core/mandate.rs**
  Modify existing code

**crates/router/src/core/payments/flows/authorize_flow.rs**
  Add:
    - function: private::get_setup_mandate_details

**crates/router/src/core/payments/flows/verfiy_flow.rs**
  Add:
    - function: private::get_setup_mandate_details