Add SSA and SCS Support to VO Loader

[duytnguyendtn]

Description

This PR extends the VO Loader to add support for IVOA's Simple Spectrum Access protocol and allow Jdaviz to load spectra, and Simple Catalog Search for Catalogs respectively. This is done by adding a dropdown at the very top which requests if users are interested in searching for Images or Spectra, which selects the appropriate protocol to pass to pyvo under the hood.

Tests in progress

Change log entry

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  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.

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• Do the proposed changes actually accomplish desired goals? Also manually run the affected example notebooks, if necessary.
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• 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?
• If new remote data is added that uses MAST, is the URI added to the cache-download.yml workflow?
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[duytnguyendtn]

I pushed up my code as-is to get feedback, as I couldn't get this particular Vuetify trick to work. Any Vuetify expert advise would be greatly appreciated!

My original plan was to have the initial dropdown ask the user for "Images" or "Spectra" (that text exactly), but have the underlying value be "sia" or "ssa" respectively for service selection down the line. Based on the Vuetify 2 docs, I should be able to accomplish it this way:

jdaviz/jdaviz/core/loaders/resolvers/virtual_observatory/vo.py

Lines 27 to 32 in 8309c63

	servicetype_choices = List(
	[
	{"label": "Images", "value": "sia"},
	{"label": "Spectra", "value": "ssa"},
	]
	).tag(sync=True)

with a small change of swapping "text" with "label" to accommodate Jdaviz's custom plugin-select component defined here:

jdaviz/jdaviz/components/plugin_select.vue

Lines 18 to 19 in 8309c63

	item-text="label"
	item-value="label"

But therein lies a problem: The plugin-select component manually forces the item-value and item-text to the same value. This raises the first question: Is there a reason why we force the two to be identical? If I change this, it will probably break things... right?

I also cannot tell if this is something that is overridable by the specific component I'm writing. Setting the item-value='value' in the VO Loader doesn't seem to do anything for me. If I do try and change it all the way in here, it also don't produce sensible output. So I can't tell if we can't override, or if my overriding is failing because of something else hidden/tucked away somewhere...

[kecnry]

we could do that, but then its confusing which (the label or the value) is expected for the user from the API for the select component. Can we just keep the user-friendly label in the UI and API and then map to what is needed for the backend call with an if-statement or dictionary lookup (or perhaps by setting 'object' in the dictionary or similar so the .selected_obj infrastructure will handle the lookup in one place)?

[duytnguyendtn]

its confusing which (the label or the value) is expected for the user from the API

Oh okay I understand the catch 22 we're under here...

map to what is needed for the backend call with an if-statement or dictionary lookup

We definitely can; it just seems like a shame to have to encode this logic if there's a built-in mechanism in Vuetify for this specific purpose. But in lieu of any better options, we might be boxed into this solution... Oh well, I'll rework that logic in this manner hopefully to sidestep this problem

[codecov]

Codecov Report

❌ Patch coverage is 54.54545% with 5 lines in your changes missing coverage. Please review.
✅ Project coverage is 84.60%. Comparing base (d237b13) to head (d8a373b).

Files with missing lines	Patch %	Lines
...z/core/loaders/resolvers/virtual_observatory/vo.py	50.00%	5 Missing ⚠️

❌ Your patch check has failed because the patch coverage (54.54%) is below the target coverage (90.00%). You can increase the patch coverage or adjust the target coverage.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4060      +/-   ##
==========================================
+ Coverage   84.57%   84.60%   +0.02%     
==========================================
  Files         205      205              
  Lines       30414    30418       +4     
==========================================
+ Hits        25724    25734      +10     
+ Misses       4690     4684       -6     

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[duytnguyendtn]

I don't think the failing tests are my doing; they seem to appear independent. At least the tests I added are passing locally for me. I'll provide this PR for review now!