Migrate Extension Requests Create to /request API with Feature Flag

[sahsisunny]

Issue Description

Migrate extension requests create API to the /request API endpoint with a feature flag.

Expected Behavior

After migration, extension requests should be handled uniformly through the /request API endpoint, with the feature flag controlling the functionality.

Current Behavior

Extension requests are currently handled through separate endpoints or mechanisms,.

Screenshots

Reproducibility

• [ ] This issue is reproducible
• [x] This issue is not reproducible

Steps to Reproduce

N/A (As this is a migration task, there are no specific steps to reproduce.)

Severity/Priority

• [ ] Critical
• [x] High
• [ ] Medium
• [ ] Low

Additional Information

Checklist

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