Test coverage of several scenarios for auth/introspect route

[azharcodeit]

What type of PR is this? (check all applicable)

• 🍕 Feature
• 🐛 Bug Fix
• 📝 Documentation
• 🧑‍💻 Refactor
• ✅ Test
• 🤖 Build or CI
• ❓ Other (please specify)

Related Issue

Related to Issue #1614

Describe this PR

This PR covers several scenarios of the auth/introspect route with tests, based on the login_required dependency injected into check_login.

Scenarios Covered:

1. Valid/correct credentials:

Test the auth/introspect endpoint with valid credentials (a valid access_token).
This test will be updated once the access_token is clarified.
Verify the behavior of the auth/introspect endpoint when no credentials are provided. Expectation is status_code = 200.

2. No credentials:

Verify the behavior of the auth/introspect endpoint when no credentials are provided. Expectation is an exception with status_code = 401 and detail = "No access token provided".

3. Invalid/incorrect credentials:

Test the auth/introspect endpoint with invalid credentials.
Expectation is an exception with status_code = 401 and detail = "Access token not valid".

Screenshots

This test intentionally fails due to the absence of a valid access_token.

Alternative Approaches Considered

Did you attempt any other approaches that are not documented in code?

Review Guide

Notes for the reviewer. How to test this change?

Command to run all tests defined in the project using pytest:

docker compose run --rm api pytest

Checklist before requesting a review

• 📖 Read the FMTM Contributing Guide: https://github.com/hotosm/fmtm/blob/main/CONTRIBUTING.md
• 📖 Read the HOT Code of Conduct: https://docs.hotosm.org/code-of-conduct
• 👷‍♀️ Create small PRs. In most cases, this will be possible.
• ✅ Provide tests for your changes.
• 📝 Use descriptive commit messages.
• 📗 Update any related documentation and include any relevant screenshots.

[optional] What gif best describes this PR or how it makes you feel?

[spwoodcock]

As discussed, we will close this for now & perhaps review testing the /auth/refresh endpoint instead at some point.