[MISC] Revert COS agent lib (16/edge)

[dragomirp]

Issue

Metrics break using the latest charm lib

Solution

Revert to the last known good patch version (0.22)

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 70.52%. Comparing base (177c558) to head (28697cb).
⚠️ Report is 2 commits behind head on 16/edge.

Additional details and impacted files

@@           Coverage Diff            @@
##           16/edge    #1472   +/-   ##
========================================
  Coverage    70.52%   70.52%           
========================================
  Files           15       15           
  Lines         4261     4261           
  Branches       691      691           
========================================
  Hits          3005     3005           
  Misses        1047     1047           
  Partials       209      209           

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