Tests: Patch TestReadyStatusEndpoint.

[gmalouf]

Summary

This PR fixes one of the 2 broken nightly build tests.

Test Plan

Existing tests should pass, including the TestReadyStatusEndpoint test on nightlies (which I ran locally before/after).

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 51.89%. Comparing base (6f65ab1) to head (5350018).
Report is 2 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #6341      +/-   ##
==========================================
- Coverage   51.90%   51.89%   -0.02%     
==========================================
  Files         653      653              
  Lines       87469    87469              
==========================================
- Hits        45399    45388      -11     
- Misses      39197    39206       +9     
- Partials     2873     2875       +2     

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