Mock crds client directly

[braingram]

Closes #339
Closes #338

Updates tests that previously mocked stpipe functions to work-around not having a test crds to instead mock the crds client allowing the stpipe functions to be called. This exposed one missing _get_crds_parameters for a test class.

As these are only test changes no regtests were run.

Tasks

• update or add relevant tests
• update relevant docstrings and / or docs/ page
• Does this PR change any API used downstream? (if not, label with no-changelog-entry-needed)
  • write news fragment(s) in changes/: echo "changed something" > changes/<PR#>.<changetype>.rst (see changelog readme for instructions)
  • run regression tests with this branch installed (stpipe@git+https://github.com/<fork>/stpipe.git@<branch>)
    • jwst regression test
    • romancal regression test

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 92.26%. Comparing base (0d5498d) to head (7009d63).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #343      +/-   ##
==========================================
+ Coverage   91.85%   92.26%   +0.41%     
==========================================
  Files          39       40       +1     
  Lines        3770     3803      +33     
==========================================
+ Hits         3463     3509      +46     
+ Misses        307      294      -13     

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