feat: restricted unnecessary api calls

[sundasnoreen12]

INF-1295

Description

Need following Improvements for the "Content Unavailable" Screen in the Discussion MFE and In-Context Sidebar.

A.C

1. Optimized API calls by restricted unnecessary parallel requests, only invoking the API returning the isEnroll attribute when needed, and prevented additional calls.
2. Ensured that unavailable content within the in-context sidebar remains hidden across all use cases.

Merge Checklist

• [ ] If your update includes visual changes, have they been reviewed by a designer? Send them a link to the Sandbox, if applicable.
• [ ] Is there adequate test coverage for your changes?

Post-merge Checklist

• [ ] Deploy the changes to prod after verifying on stage or ask @openedx/edx-infinity to do it.
• [ ] 🎉 🙌 Celebrate! Thanks for your contribution.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 92.83%. Comparing base (4914f51) to head (ccd3b96).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #683 +/- ## ======================================= Coverage 92.82% 92.83% ======================================= Files 158 158 Lines 3304 3307 +3 Branches 896 899 +3 ======================================= + Hits 3067 3070 +3 Misses 218 218 Partials 19 19 ```

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