Fix timing issue in client tests

[acwest]

Fix issue in client tests due to issue in test recording library where multiple simultaneous requests have the same signature.
A better fix would be to add an X-Request-Id header to POST calls that can have this issue, but I believe go-vcr doesn't handle that properly either, so we might have to update and/or fix it. For now, splitting up the two POST calls should fix the tests.

📚 References

🔬 Testing

To test this, just re-run all Checks and tests. Before this fix, that was about 80% likely to fail, now it is succeeding 100% of the time (5 runs so far on this PR, I'm going to keep clicking rerun while I work on other things)

📝 Checklist

• All new/changed/fixed functionality is covered by tests (or N/A)
• I have added documentation for all new/changed functionality (or N/A)

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 89.21%. Comparing base (e6a076f) to head (5b7146a).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1131   +/-   ##
=======================================
  Coverage   89.21%   89.21%           
=======================================
  Files         130      130           
  Lines       18060    18060           
=======================================
  Hits        16112    16112           
  Misses       1379     1379           
  Partials      569      569