bugfix for viewer rename when viewer ID is different from reference name

[bmorris3]

#2338 implemented viewer reference name updates, with an option to update viewer IDs as well. That feature is intended for internal use in lcviz.

Subsequent development in lcviz exposed a bug in the jdaviz method when update_id=True (spacetelescope/lcviz#35). Each viewer's entry in the viewer store has a hidden attr _reference_id which should match viewer_item['id'], but #2338 did not update that attr.

Also, the ID is only updated if update_id=True and viewer_item['id'] == old_reference, but the latter condition is satisfied if the ID matches the reference name (which is not required elsewhere).

This PR adds the missing update to the hidden reference_id attr, and removes the unnecessary second condition for updating the ID.

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.
• After merge, any internal documentations need updating (e.g., JIRA, Innerspace)?

[bmorris3]

The test failure in this PR is identical to the one that #2478 is intended to fix.

[pllim]

Looks like you added this logic back in #2338 . Why was the == check necessary back then but not anymore?

[kecnry]

the original implementation in lcviz had just the == logic without the update_id switch, so I think it just came with that accidentally without thinking about if we still needed it.

[bmorris3]

It wasn't necessary then or now, hence the bugfix.

[pllim]

Code looks like code.

[kecnry]

Works locally with spacetelescope/lcviz#35, thanks!!

[kecnry]

@bmorris3 - I think this should pass CI once its rebased 🤞

[codecov]

Codecov Report

Attention: 1 lines in your changes are missing coverage. Please review.

Files	Coverage Δ
jdaviz/app.py	85.18% <50.00%> (-0.09%)	⬇️

📢 Thoughts on this report? Let us know!.

[pllim]

Ooof, you will need to manually backport or change the milestone.