Fix compute_scale when fiducial coordinates are outside bounding box

[astrofrog]

Description

This fixes a corner case in compute_scale when the fiducial coordinates provided are outside of the bounding box.

This is needed if the bounding box on data is not reset, and in order to be compatible with spacetelescope/gwcs#498

cc @bmorris3

Change log entry

• Is a change log needed? If yes, is it added to CHANGES.rst? If you want to avoid merge conflicts,
  list the proposed change log here for review and add to CHANGES.rst before merge. If no, maintainer
  should add a no-changelog-entry-needed label.

Checklist for package maintainer(s)

This checklist is meant to remind the package maintainer(s) who will review this pull request of some common things to look for. This list is not exhaustive.

• Are two approvals required? Branch protection rule does not check for the second approval. If a second approval is not necessary, please apply the trivial label.
• Do the proposed changes actually accomplish desired goals? Also manually run the affected example notebooks, if necessary.
• Do the proposed changes follow the STScI Style Guides?
• Are tests added/updated as required? If so, do they follow the STScI Style Guides?
• Are docs added/updated as required? If so, do they follow the STScI Style Guides?
• Did the CI pass? If not, are the failures related?
• Is a milestone set? Set this to bugfix milestone if this is a bug fix and needs to be released ASAP; otherwise, set this to the next major release milestone. Bugfix milestone also needs an accompanying backport label.
• After merge, any internal documentations need updating (e.g., JIRA, Innerspace)?

[astrofrog]

I don't think this needs a changelog entry as as far as users are concerned it won't have an impact yet, since jdaviz disables the bounding box by default. It's more to future-proof if we do want to retain the bounding boxes.

[codecov]

Codecov Report

Attention: Patch coverage is 60.00000% with 2 lines in your changes are missing coverage. Please review.

Project coverage is 88.71%. Comparing base (b89784c) to head (ce15aeb).
Report is 2 commits behind head on main.

Files	Patch %	Lines
jdaviz/configs/imviz/wcs_utils.py	60.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2887      +/-   ##
==========================================
- Coverage   88.72%   88.71%   -0.01%     
==========================================
  Files         111      111              
  Lines       17102    17106       +4     
==========================================
+ Hits        15174    15176       +2     
- Misses       1928     1930       +2     

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[pllim]

@bmorris3 should review this one. And also since he mentioned that he lifted this code from jwst, I wonder if a similar patch has to go to jwst also.

[bmorris3]

I'm re-milestoning this one to 4.0, since the related upstream GWCS changes (spacetelescope/gwcs#498) are in draft pending strategizing and discussion from @nden and @mcara.

[bmorris3]

With the latest changes to spacetelescope/gwcs#498, this will work for us with one further change, in astrofrog#5.

[kecnry]

@bmorris3 - is this still needed/used anywhere? Can we remove the entire if-statement?