reorder anyOf in apcorr schema to work around asdf bug

[braingram]

The asdf datatype validator raises an exception instead of yielding leading to incorrect validation failure for the anyOf schema combiner in the apcorr ref file schema (xref: asdf-format/asdf#1903).

This PR works around the issue (until an asdf fix can be made and released) by reordering the anyOf to check for None first (when this succeeds the remainder of the anyOf will not be evaluated avoiding the asdf bug).

Tasks

• Update or add relevant rad tests.
• Update relevant docstrings and / or docs/ page.
• Does this PR change any schema files?
  • Schema changes were discussed at RAD Review Board meeting.
• 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 below for change types).
  • Start a romancal regression test (https://github.com/spacetelescope/RegressionTests/actions/workflows/romancal.yml) with this branch installed ("git+https://github.com/<fork>/rad@<branch>").
  • Update relevant roman_datamodels utilities and tests.

News fragment change types:

• changes/<PR#>.feature.rst: new feature
• changes/<PR#>.bugfix.rst: fixes an issue
• changes/<PR#>.doc.rst: documentation change
• changes/<PR#>.removal.rst: deprecation or removal of public API
• changes/<PR#>.misc.rst: infrastructure or miscellaneous change

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 96.61%. Comparing base (6094d86) to head (32af770).
Report is 5 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #542      +/-   ##
==========================================
+ Coverage   96.59%   96.61%   +0.02%     
==========================================
  Files           4        4              
  Lines         264      266       +2     
==========================================
+ Hits          255      257       +2     
  Misses          9        9              

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[PaulHuwe]

Do we need to follow this pattern for future anyOfs containing None like this?

[PaulHuwe]

LGTM

[braingram]

Do we need to follow this pattern for future anyOfs containing None like this?

I would say no. When asdf-format/asdf#1904 is merged asdf will handle the current schema on rad main without issue. The schema reordering avoids the bug (and otherwise functions the same way).

I do think it's worth adding the test in spacetelescope/roman_datamodels#460 since we want to be sure None values are accepted. I'll open that PR once this is merged.