enhancement: update billing plan endpoints docs to show sample return data

[chimeziriobioha]

Description

Update billing plan endpoints docs to show samples of expected data so frontend developers can easily integrate with the backend. Endpoint docs updated include:

• /api/v1/organisations/{organisation_id}/billing-plans
• /api/v1/organisations/billing-plans
• /api/v1/organisations/billing-plans/{billing_plan_id}
• /api/v1/organisations/billing-plans/{billing_plan_id}

Related Issue

[FIX]: Add Expected Data Samples To Docs For All Billing Plan Endpoints #941

Motivation and Context

Frontend developers and others viewing the backend docs should be able to know exactly what to expect from each endpoint.

How Has This Been Tested?

• Unit Tests: Added tests to validate successful and failed requests as expected.
  • Test Environment: Mocked database; to avoid interference with the production environment.

Screenshots:

Before The Update

After The Update

Types of changes

• [x] Bug fix (non-breaking change which adds functionality)

  Checklist:

  • [x] My code follows the code style of this project.
  • [x] My change requires a change to the documentation.
  • [x] I have updated the documentation accordingly.
  • [x] I have read the CONTRIBUTING document.
  • [x] I have added tests to cover my changes.
  • [x] All new and existing tests passed.

[JoshuaOloton]

This issue looks resolved already @traderstechie

[chimeziriobioha]

This issue looks resolved already @traderstechie

Not really @JoshuaOloton . My PR is not about the endpoint functionality, but the docs that shows what's returned in the data key, which tells frontend guys what to expect from the endpoint.

[johnson-oragui]

You might as well fix the rest of the docs if this qualifies as an issue.

[chimeziriobioha]

You might as well fix the rest of the docs if this qualifies as an issue.

I believe it's something that should be done. If not now, then later. Maybe this one will bring attention to it. Without good docs, it'll be hard for non-contributors to integrate the product. It doesn't particularly matter if it qualifies as an issue now or not.