Fix model fitting plugin bugs

[rosteen]

Fixes #1144, as well as a bug I noticed that doesn't have an issue, where the data dropdown menu wasn't properly getting populated with spatial subsets when they were created.

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 change log needed? If yes, is it added to CHANGES.rst?
• Is a milestone set? Milestone is only currently required for PRs related to Imviz MVP.
• After merge, any internal documentations need updating (e.g., JIRA, Innerspace)?

[pllim]

Do we not need this?

[rosteen]

No, and in fact it was breaking it because now it's listening for messages that don't have a viewer_id attached. This was a minuscule performance improvement to not update the data dropdown on irrelevant AddData messages.

[codecov]

Codecov Report

Merging #1176 (a9e4306) into main (be1d987) will increase coverage by 0.00%.
The diff coverage is 50.00%.

@@           Coverage Diff           @@
##             main    #1176   +/-   ##
=======================================
  Coverage   76.37%   76.38%           
=======================================
  Files          87       87           
  Lines        6723     6724    +1     
=======================================
+ Hits         5135     5136    +1     
  Misses       1588     1588           

Impacted Files	Coverage Δ
...igs/default/plugins/model_fitting/model_fitting.py	31.29% <50.00%> (+0.23%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update be1d987...a9e4306. Read the comment docs.

[rosteen]

Not sure how I messed up the PR number in the changelog, good catch 😵

[camipacifici]

I don't get anymore the "ValueError: No data found with the label 'Subset 1'" when trying to fit the spectrum from a collapsed spatial subset!

[pllim]

@camipacifici said on Slack: It still chokes when selecting a sub-subset (as expected right?).

Can someone please confirm whether this is out of scope here or not? Thanks!

[rosteen]

It's not clear to me what use case is failing, I assume it's the not-actually-intended use case and is thus out of scope. Selecting a spectral subset to apply to the collapsed spectrum of a spatial subset works.

[kecnry]

seems like a straightforward fix for now. We can handle the subset styling and not allowing mixing spectral and spatial subsets in future work.

[pllim]

Approving by proxy since Cami okayed this.