plugin-action-button component for consistent styling

[kecnry]

Description

This pull request creates a new plugin-action-button UI component for more developer-friendly consistent-styling of buttons in plugins.

• better consistency for coloring by passing :results_isolated_to_plugin="true/false"
• update UI style guide
• adds spinner for "Calculate" button in aperture photometry, "Search" in catalogs, and "Apply RGB Presets" in plot options (previously wasn't available because the spinner logic from plugins: disable action button while computing #2560 was isolated to add-results components)
• changes color of buttons in subset plugin since clicking them affects the app itself

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

All modified and coverable lines are covered by tests ✅

Comparison is base (ac3078a) 90.80% compared to head (cf98367) 90.80%.
Report is 1 commits behind head on main.

❗ Current head cf98367 differs from pull request most recent head 4e9d41e. Consider uploading reports for the commit 4e9d41e to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2571      +/-   ##
==========================================
- Coverage   90.80%   90.80%   -0.01%     
==========================================
  Files         160      160              
  Lines       19394    19396       +2     
==========================================
+ Hits        17611    17612       +1     
- Misses       1783     1784       +1     

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[rosteen]

This looks good to me so far but I want to do just a little more testing (I did Imviz but not Specviz) in the morning before hitting Approve.

[rosteen]

Looks good to me after the one suggestion I left above.