JP-3687: fix outlier_detection failures when run outside pipeline

[emolter]

Resolves JP-3687

Closes #8640

This PR addresses a bug that occurs when the outlier_detection step is run outside the pipeline, i.e., loading the datamodel from file instead of passing it in as a ModelContainer. In that case, the wcs.array_shape attribute sometimes does not get saved (saving of this attribute was added to gwcs within the past year, so the behavior is version-dependent). This PR sets the wcs.array_shape explicitly.

Checklist for PR authors (skip items if you don't have permissions or they are not applicable)

• added entry in CHANGES.rst within the relevant release section
• updated or added relevant tests
• updated relevant documentation
• added relevant milestone
• added relevant label(s)
• ran regression tests, post a link to the Jenkins job below.
  How to run regression tests on a PR
• All comments are resolved
• Make sure the JIRA ticket is resolved properly

[emolter]

Regression tests started here, using the new GitHub Actions workflow (hope that works!) https://github.com/spacetelescope/RegressionTests/actions/runs/9940607341

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 59.61%. Comparing base (4b77a5e) to head (d433757).

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #8645   +/-   ##
=======================================
  Coverage   59.60%   59.61%           
=======================================
  Files         391      391           
  Lines       39286    39287    +1     
=======================================
+ Hits        23418    23419    +1     
  Misses      15868    15868           

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[emolter]

separate regtests with same changes started here on Jenkins: https://plwishmaster.stsci.edu:8081/job/RT/job/JWST-Developers-Pull-Requests/1605/

[emolter]

all regtest failures are unrelated

[melanieclarke]

LGTM! Just a small comment grammar suggestion.