Fix miri avg_dark regtest

[hbushouse]

This PR changes the test of the average_dark capability in the calwebb_detector1 pipeline so that it no longer uses one of the same datasets that's already used in another test in the same regtest module. That causes issues with outputs clobbering one another. All the new input/output files have been loaded to Artifactory and the new regtest passes locally.

Checklist for maintainers

• added entry in CHANGES.rst within the relevant release section
• updated or added relevant tests
• updated relevant documentation
• added relevant milestone
• added relevant label(s)
• ran regression tests, post a link to the Jenkins job below.
  How to run regression tests on a PR
• Make sure the JIRA ticket is resolved properly

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 56.26%. Comparing base (2fb073e) to head (1b7766e).
Report is 41 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff             @@
##           master    #8446       +/-   ##
===========================================
- Coverage   75.31%   56.26%   -19.05%     
===========================================
  Files         474      390       -84     
  Lines       38965    38866       -99     
===========================================
- Hits        29345    21868     -7477     
- Misses       9620    16998     +7378     

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