JP-3896: Deprecate or remove various assign_wcs utility functions

[emolter]

Resolves JP-3896

Closes #9218

This PR removes various unused utility functions from assign_wcs, as follows:

• _domain_to_bounding_box: unused, and private
• reproject: part of __all__ of assign_wcs.util but unused elsewhere in the pipeline, and not in the documentation (because not part of __all__ in the top-level step). There are also multiple functions of the same name in stcal with similar (identical?) functionality. Because this was in the __all__ though, I have deprecated it here instead of removing right away.
• compute_fiducial: Only used inside a test of the resample step, and the test was easy to modify such that this was not needed.
• is_fits: unused
• get_num_msa_open_shutters: unused

Before this is merged, we need to know if any of these are used outside the pipeline. If they are, they should be added to the __all__ of the top-level step so their API renders in readthedocs, and if not, we can safely remove them.

Tasks

• request a review from someone specific, to avoid making the maintainers review every PR
• add a build milestone, i.e. Build 11.3 (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 below for change types)
  • 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

news fragment change types...

• changes/<PR#>.general.rst: infrastructure or miscellaneous change
• changes/<PR#>.docs.rst
• changes/<PR#>.stpipe.rst
• changes/<PR#>.datamodels.rst
• changes/<PR#>.scripts.rst
• changes/<PR#>.set_telescope_pointing.rst
• changes/<PR#>.pipeline.rst

stage 1

• changes/<PR#>.group_scale.rst
• changes/<PR#>.dq_init.rst
• changes/<PR#>.emicorr.rst
• changes/<PR#>.saturation.rst
• changes/<PR#>.ipc.rst
• changes/<PR#>.firstframe.rst
• changes/<PR#>.lastframe.rst
• changes/<PR#>.reset.rst
• changes/<PR#>.superbias.rst
• changes/<PR#>.refpix.rst
• changes/<PR#>.linearity.rst
• changes/<PR#>.rscd.rst
• changes/<PR#>.persistence.rst
• changes/<PR#>.dark_current.rst
• changes/<PR#>.charge_migration.rst
• changes/<PR#>.jump.rst
• changes/<PR#>.clean_flicker_noise.rst
• changes/<PR#>.ramp_fitting.rst
• changes/<PR#>.gain_scale.rst

stage 2

• changes/<PR#>.assign_wcs.rst
• changes/<PR#>.badpix_selfcal.rst
• changes/<PR#>.msaflagopen.rst
• changes/<PR#>.nsclean.rst
• changes/<PR#>.imprint.rst
• changes/<PR#>.background.rst
• changes/<PR#>.extract_2d.rst
• changes/<PR#>.master_background.rst
• changes/<PR#>.wavecorr.rst
• changes/<PR#>.srctype.rst
• changes/<PR#>.straylight.rst
• changes/<PR#>.wfss_contam.rst
• changes/<PR#>.flatfield.rst
• changes/<PR#>.fringe.rst
• changes/<PR#>.pathloss.rst
• changes/<PR#>.barshadow.rst
• changes/<PR#>.photom.rst
• changes/<PR#>.pixel_replace.rst
• changes/<PR#>.resample_spec.rst
• changes/<PR#>.residual_fringe.rst
• changes/<PR#>.cube_build.rst
• changes/<PR#>.extract_1d.rst
• changes/<PR#>.resample.rst

stage 3

• changes/<PR#>.assign_mtwcs.rst
• changes/<PR#>.mrs_imatch.rst
• changes/<PR#>.tweakreg.rst
• changes/<PR#>.skymatch.rst
• changes/<PR#>.exp_to_source.rst
• changes/<PR#>.outlier_detection.rst
• changes/<PR#>.tso_photometry.rst
• changes/<PR#>.stack_refs.rst
• changes/<PR#>.align_refs.rst
• changes/<PR#>.klip.rst
• changes/<PR#>.spectral_leak.rst
• changes/<PR#>.source_catalog.rst
• changes/<PR#>.combine_1d.rst
• changes/<PR#>.ami.rst

other

• changes/<PR#>.wfs_combine.rst
• changes/<PR#>.white_light.rst
• changes/<PR#>.cube_skymatch.rst
• changes/<PR#>.engdb_tools.rst
• changes/<PR#>.guider_cds.rst

[emolter]

regression tests started here: https://github.com/spacetelescope/RegressionTests/actions/runs/13525309517

edit: all passing

[codecov]

Codecov Report

Attention: Patch coverage is 50.00000% with 1 line in your changes missing coverage. Please review.

Project coverage is 73.72%. Comparing base (16aa8b0) to head (5e44593).
Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
jwst/assign_wcs/util.py	50.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #9221      +/-   ##
==========================================
+ Coverage   73.66%   73.72%   +0.05%     
==========================================
  Files         368      368              
  Lines       36392    36331      -61     
==========================================
- Hits        26808    26784      -24     
+ Misses       9584     9547      -37     

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[emolter]

@nden @drlaw1558 I thought you two would be the people most likely to know whether any of these are being used anywhere outside the pipeline.

[drlaw1558]

@emolter I'm not aware of any such use beyond the pipeline; I can bounce it off the instrument teams though.