Update output_checkers interface to properly report MISSINGPRODUCT files for deletion from test comparison directory

[mindyls]

Requested Update

Description

• Since converting output_checkers to an interface, the MISSINGPRODUCT file identification no longer works to identify the files in the test comparison directory for deletion. Since we are now running output comparisons on a single file at a time, we no longer track the missing comparisons in the tests/outputs directory properly, so we can no longer automatically delete the files from the output comparison directory of "correct" outputs when there is not a corresponding product in the current run. Note the MISSINGCOMPS (copying from current outputs to test comparison directory) and BADCOMPARES (copying from current outputs to test compmarison directory) still work (since we can determine those on a one to one basis - so copying the files out of the current run to the test comparison directory still works, just deleting from the test comparison directory will not work).
• Also note the cp_MISSINGCOMPARE.txt actually is NOT correct - it only contains the final file that was identified as needing copied (since we are running one at a time).

Background and Motivation

• https://github.com/NRLMMD-GEOIPS/geoips/blob/main/geoips/plugins/modules/procflows/single_source.py#L1903
• That is probably where we would need to track what products were produced, and the full list of products in the compare path.

Alternative Solutions

• [ OPTIONAL: If appropriate, list alternative fixes that could be considered]

Environment

• [ IF APPROPRIATE: Corresponding repository versions ]

Code to demonstrate issue

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Checklist for Completion

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