TST: Re-enable test_moment_maps

[pllim]

Description

This pull request is to re-enable and fix a failing test.

Fixes #948

Follow-up of #547

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]

I also noticed a lot of this:

WARNING specutils.spectra.spectrum1d:spectrum1d.py:205 Input WCS indicates that the spectral axis is not last. Reshaping arrays to put spectral axis last.

I suspect there are some unnecessary data translation going on in the background but fixing that is out of scope here.

[codecov]

Codecov Report

Merging #1024 (dc92c56) into main (9fb18f6) will increase coverage by 0.40%.
The diff coverage is n/a.

❗ Current head dc92c56 differs from pull request most recent head a32ddca. Consider uploading reports for the commit a32ddca to get more accurate results

@@            Coverage Diff             @@
##             main    #1024      +/-   ##
==========================================
+ Coverage   72.69%   73.09%   +0.40%     
==========================================
  Files          75       75              
  Lines        5669     5669              
==========================================
+ Hits         4121     4144      +23     
+ Misses       1548     1525      -23     

Impacted Files	Coverage Δ
...configs/cubeviz/plugins/moment_maps/moment_maps.py	78.15% <0.00%> (+19.32%)	⬆️

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[pllim]

xref #1025