Add tests to search functionality for GET /endorsements

[Chethan64]

Issue Description

Add unit tests and integration tests to the search functionality (#95) for GET /endorsements by skillID or userID

Screenshots

Severity/Priority

• Critical
• High
• Medium
• Low

Additional Information

Design document - https://docs.google.com/document/d/1vGNTwzyecD93LXJ_Y1Mk7hz4Km8uFs4y6EHsA-4j1ac/edit (for the feature)

• Implementing RQL-based query parameters as part of the search on the already existing GET /endorsements endpoint
• Add unit tests and integration tests to the search functionality
• Additional information about the feature can be found at V1 Search Functionality for GET/ endorsments #95 and in the design document

Checklist

• I have read and followed the project's code of conduct.
• I have searched for similar issues before creating this one.
• I have provided all the necessary information to understand and reproduce the issue.
• I am willing to contribute to the resolution of this issue.