don't reset redshift when adding results from plugins

[kecnry]

Description

This pull request avoids resetting the redshift to zero everytime results from a plugin are added back to the app/viewer. Note that adding new data not from a plugin will reset the app-wide redshift to the value (defaulting to zero) in that spectrum - we may want to reconsider this behavior in the future.

Fixes #1692

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)?

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (main@a8336af). Click here to learn what that means.
Patch coverage: 50.00% of modified lines in pull request are covered.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1915   +/-   ##
=======================================
  Coverage        ?   88.52%           
=======================================
  Files           ?       95           
  Lines           ?    10617           
  Branches        ?        0           
=======================================
  Hits            ?     9399           
  Misses          ?     1218           
  Partials        ?        0           

Impacted Files	Coverage Δ
...z/configs/default/plugins/line_lists/line_lists.py	74.67% <50.00%> (ø)

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[javerbukh]

Works for me!

[pllim]

LGTM now. Thanks for adding the test!

[lumberbot-app]

Owee, I'm MrMeeseeks, Look at me.

There seem to be a conflict, please backport manually. Here are approximate instructions:

1. Checkout backport branch and update it.

git checkout v3.1.x
git pull

2. Cherry pick the first parent branch of the this PR on top of the older branch:

git cherry-pick -x -m1 b7c88539e5e938407b601d4c4d49e551e71c27f6

3. You will likely have some merge/cherry-pick conflict here, fix them and commit:

git commit -am "Backport PR #1915: don't reset redshift when adding results from plugins"

4. Push to a named branch:

git push YOURFORK v3.1.x:auto-backport-of-pr-1915-on-v3.1.x

5. Create a PR against branch v3.1.x, I would have named this PR:

"Backport PR #1915 on branch v3.1.x (don't reset redshift when adding results from plugins)"

And apply the correct labels and milestones.

Congratulations — you did some good work! Hopefully your backport PR will be tested by the continuous integration and merged soon!

Remember to remove the Still Needs Manual Backport label once the PR gets merged.

If these instructions are inaccurate, feel free to suggest an improvement.

[pllim]

Hmm @kecnry do you want to manually backport this or should we change milestone and move the change log?

[kecnry]

I'll backport