Remove dev feature flag from GET /tasks API

Issue Description

This API has been live on prod for a long time but the dev feature flag has not been removed.
Remove the dev FF from backend and all other repos where its being used

Usages in other repos

1. discord-slash-commands - All usages use FF ✅
2. mobile-app - All usages use FF ✅
3. website-dashboard - All usages use FF ✅
4. website-status - All usages use FF ✅

This is a subtask of #2075

Expected Behavior

Current Behavior

Screenshots

NA

Reproducibility

• This issue is reproducible
• This issue is not reproducible

Steps to Reproduce

NA

Severity/Priority

• Critical
• High
• Medium
• Low

Additional Information

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.

Search the website-backend repository for the GET /tasks API and its dev feature-flag checks, then inspect the listed discord-slash-commands, mobile-app, website-dashboard, and website-status repositories for related usages. Confirm the flag can be removed without changing the live API behavior, and verify that no listed repository still depends on the flag.