JP-3955: NIRCam DHS assign_wcs updates

[tapastro]

Resolves JP-3955

This PR builds WCS objects for each stripe present in a DHS substripe observation.

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)
  • 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

❌ Patch coverage is 23.87387% with 169 lines in your changes missing coverage. Please review.
✅ Project coverage is 82.32%. Comparing base (94c0254) to head (0f0786e).
⚠️ Report is 6 commits behind head on main.

Files with missing lines	Patch %	Lines
jwst/assign_wcs/nircam.py	7.35%	63 Missing ⚠️
jwst/lib/reffile_utils.py	46.93%	52 Missing ⚠️
jwst/lib/pipe_utils.py	2.56%	38 Missing ⚠️
jwst/assign_wcs/util.py	5.88%	16 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #9836      +/-   ##
==========================================
- Coverage   83.38%   82.32%   -1.06%     
==========================================
  Files         366      366              
  Lines       37770    37941     +171     
==========================================
- Hits        31493    31234     -259     
- Misses       6277     6707     +430     

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