JP-4273: Expect multiple apertures for PSF reference file

[melanieclarke]

Resolves JP-4273

Update handling for spectral PSF reference files, to match a new schema. This is necessary to support optimal extraction for NIRSpec, which needs to provide PSFs for multiple slits in the same reference file.

Requires spacetelescope/stdatamodels#734

Tasks

• If you have a specific reviewer in mind, tag them.
• add a build milestone, i.e. Build 12.0 (use the latest build if not sure)
• Does this PR change user-facing code / API? (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)
    • if your change breaks step-level or public API (as defined in the docs), also add a changes/<PR#>.breaking.rst news fragment
  • update or add relevant tests
  • update relevant docstrings and / or docs/ page
  • start a regression test and include a link to the running job (click here for instructions)
    • Do truth files need to be updated ("okified")?
      • after the reviewer has approved these changes, run okify_regtests to update the truth files
• if a JIRA ticket exists, make sure it is resolved properly

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 86.39%. Comparing base (a5eb979) to head (f5b36ae).

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #10516   +/-   ##
=======================================
  Coverage   86.38%   86.39%           
=======================================
  Files         373      373           
  Lines       40068    40077    +9     
=======================================
+ Hits        34614    34623    +9     
  Misses       5454     5454           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[melanieclarke]

Regtests: https://github.com/spacetelescope/RegressionTests/actions/runs/25517109460

All passing.