JP-3349: add keyword_filter ref to gain.schema

[braingram]

Resolves JP-3349

Closes spacetelescope/jwst#7832

Add $ref to keyword_filter schema to gain schema to support the meta.instrument.filter parameter added to the corresponding miri gain crds file.

Checklist

• added entry in CHANGES.rst (either in Bug Fixes or Changes to API)
• updated relevant tests
• updated relevant documentation
• updated relevant milestone(s)
• added relevant label(s)

[codecov]

Codecov Report

Patch and project coverage have no change.

Comparison is base (80dd764) 64.01% compared to head (8e83a42) 64.01%.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #197   +/-   ##
=======================================
  Coverage   64.01%   64.01%           
=======================================
  Files         101      101           
  Lines        5558     5558           
=======================================
  Hits         3558     3558           
  Misses       2000     2000           

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[tapastro]

Looks good, was just curious to see if we should expect regression test issues stemming from this change, so I started a run here: https://plwishmaster.stsci.edu:8081/job/RT/job/JWST-Developers-Pull-Requests/871/

[braingram]

Looks good, was just curious to see if we should expect regression test issues stemming from this change, so I started a run here: https://plwishmaster.stsci.edu:8081/job/RT/job/JWST-Developers-Pull-Requests/871/

Thanks for starting the regtests! I was waiting for the server to be free and got distracted :)

[braingram]

Woot! Test run showed no errors:
https://plwishmaster.stsci.edu:8081/blue/organizations/jenkins/RT%2FJWST-Developers-Pull-Requests/detail/JWST-Developers-Pull-Requests/871/tests

[tapastro]

🎉