[DPE-8426] Fix refresh tests

[dragomirp]

Wait for idleness in all blocked cases. Seems to be a problem on 16/edge publish: https://github.com/canonical/postgresql-operator/actions/runs/18670358815/job/53266326487#step:10:16

Checklist

• I have added or updated any relevant documentation.
• I have cleaned any remaining cloud resources from my accounts.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 66.83%. Comparing base (0f14536) to head (9269195).
⚠️ Report is 2 commits behind head on 16/edge.

❌ Your project status has failed because the head coverage (66.83%) is below the target coverage (70.00%). You can increase the head coverage or adjust the target coverage.

Additional details and impacted files

@@           Coverage Diff            @@
##           16/edge    #1248   +/-   ##
========================================
  Coverage    66.83%   66.83%           
========================================
  Files           17       17           
  Lines         4360     4360           
  Branches       675      675           
========================================
  Hits          2914     2914           
  Misses        1249     1249           
  Partials       197      197           

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