Fix followers/following tests

[arnavk23]

• Replace skipped followers/following checks with real coverage: reuse the fetched profile, assert return types, and verify list lengths when profile counts are available.
• Fixes TODO: Fix tests for GitHub.followers and GitHub.following #236

Testing

julia --project -e 'using Pkg; Pkg.test(; test_args=["read_only_api_tests"])' (passes with provided token; the suite still has the same pre-existing broken cases elsewhere).

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 58.65%. Comparing base (97e94e4) to head (e87d667).

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #251      +/-   ##
==========================================
+ Coverage   58.45%   58.65%   +0.20%     
==========================================
  Files          37       37              
  Lines         982      982              
==========================================
+ Hits          574      576       +2     
+ Misses        408      406       -2     

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[arnavk23]

@DilumAluthge All tests pass. Please review this pr. Thanks!

[DilumAluthge]

Thanks for working on this one as well!

Regarding the changes on lines 108 through 120 (the changes around the check_membership() tests - could you move those changes out into a separate pull request? Then we can keep this PR focused just on followers/following.

[arnavk23]

Thanks for working on this one as well!

@DilumAluthge done as suggested.

[DilumAluthge]

I think we might add some utility functionality in #252 that we can then use in this PR. So it might make sense for us to try to finish up #252 first - then we don't have to duplicate our work.