Remove processing module creation from mock_ImagingPlane

[h-mayorquin]

Motivation

The mock_ImagingPlane is creating a processing module but then it does not do anythign with it. This seems like a side effect that should not be there.

Checklist

• Did you update CHANGELOG.md with your changes?
• Have you checked our Contributing document?
• Have you ensured the PR clearly describes the problem and the solution?
• Is your contribution compliant with our coding style? This can be checked running ruff check . && codespell from the source directory.
• Have you checked to ensure that there aren't other open Pull Requests for the same change?
• Have you included the relevant issue number using "Fix #XXX" notation where XXX is the issue number? By including "Fix #XXX" you allow GitHub to close issue #XXX when the PR is merged.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 94.83%. Comparing base (7a38529) to head (b26e9b1).
⚠️ Report is 30 commits behind head on dev.

Additional details and impacted files

@@           Coverage Diff           @@
##              dev    #2099   +/-   ##
=======================================
  Coverage   94.83%   94.83%           
=======================================
  Files          28       28           
  Lines        2751     2751           
  Branches      708      708           
=======================================
  Hits         2609     2609           
  Misses         82       82           
  Partials       60       60           

Flag	Coverage Δ
integration	74.15% <ø> (ø)
unit	84.84% <ø> (ø)

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[rly]

Good catch. Thanks, @h-mayorquin