disallow gaussian smooth output as input

[kecnry]

Description

This pull request excludes the output from the gaussian smooth plugin to be a valid input back into the plugin, preventing a vertical "shift" after clicking the smooth button when only one input data was available.

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)?

[pllim]

Do you think in the future we would need a generic version of this, maybe something like this?

Suggested change

	def not_from_this_plugin(data):
	def not_from_plugin(data, plugin_name="self"):

For example, is there a situation where we would say "plugin X cannot take output from plugin Y"?

[kecnry]

The current framework doesn't allow for that (there is no way to set the kwargs that would get passed on). Instead, the plugin could create and pass its own callable to the filter:

def not_from_something_specific(data):
    return data.meta.get('Plugin', None) not in ('something', 'specific')

dataset.add_filter(not_from_something_specific)

or if we find we re-use something often, we could migrate it directly into the dataset component.

[pllim]

OK, fine as-is then. If it is not easy, no point to worry about use case that does not yet exist.

[codecov]

Codecov Report

Patch coverage: 100.00% and no project coverage change.

Comparison is base (7ffaa26) 91.62% compared to head (e0a1fd6) 91.63%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2239   +/-   ##
=======================================
  Coverage   91.62%   91.63%           
=======================================
  Files         148      148           
  Lines       16535    16538    +3     
=======================================
+ Hits        15151    15154    +3     
  Misses       1384     1384           

Impacted Files	Coverage Δ
...default/plugins/gaussian_smooth/gaussian_smooth.py	97.75% <100.00%> (+0.02%)	⬆️
...gins/gaussian_smooth/tests/test_gaussian_smooth.py	100.00% <100.00%> (ø)
jdaviz/core/template_mixin.py	93.11% <100.00%> (+0.01%)	⬆️

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[pllim]

LGTM. Thanks!