test: container client tests refactor

[piksel]

Refactoring of the container client tests.

• The tests should now explicitly tell what they are testing for and the requirements
• Fixed the test data so that it doesn't contain discrepancies
• The mock client is now being fully reset between tests (no shared state) and only support the calls that is expected

[codecov]

Codecov Report

Merging #1117 (536035c) into main (2c86956) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main    #1117   +/-   ##
=======================================
  Coverage   61.96%   61.96%           
=======================================
  Files          22       22           
  Lines        1438     1438           
=======================================
  Hits          891      891           
  Misses        463      463           
  Partials       84       84           

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