[CLIENT-3846] Speed up dev tests

[juliannguyen4]

Time to run all admin tests: reduced from 10 minutes to < 3 minutes

Extra changes:

• Prevent race conditions (false positive results) in admin tests (TODO: find way to customize interval for server to update admin stuff). False positive results often cause noise in the dev and stage tests, which can block promoting the latest revision in the dev branch to stage

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 82.45%. Comparing base (34c2e3f) to head (f2ac553).
⚠️ Report is 9 commits behind head on dev.

Additional details and impacted files

@@            Coverage Diff             @@
##              dev     #856      +/-   ##
==========================================
+ Coverage   82.35%   82.45%   +0.09%     
==========================================
  Files          99       99              
  Lines       14379    14496     +117     
==========================================
+ Hits        11842    11952     +110     
- Misses       2537     2544       +7     

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