Reduce redundant API calls in getPrivileges() using courseId cache #13454

[prachitjain]

#13454 This is the issue number.

Fixes #13454
These changes reduces the redundant api calls.

Outline of Solution

1. Created a map (At class level) that stores previously fetches results.
2. Wrapped each API call with shareReplay.
3. Now loadConstructorPrivilege is called once per unique courseId

[github-actions]

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