JP-3532: MRS 1d residual fringe treatment of negative values

[drlaw1558]

Resolves JP-3532 by properly masking zero or negative-valued spectra instead of only zero-valued spectra.

Closes #8260

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

[jemorrison]

Simple fix

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (557c3fa) 75.18% compared to head (2efa12f) 77.37%.
Report is 2 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #8261      +/-   ##
==========================================
+ Coverage   75.18%   77.37%   +2.18%     
==========================================
  Files         470      451      -19     
  Lines       38549    35270    -3279     
==========================================
- Hits        28983    27290    -1693     
+ Misses       9566     7980    -1586     

Flag	Coverage Δ		*Carryforward flag
nightly	77.37% <ø> (ø)		Carriedforward from 557c3fa

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[hbushouse]

regression tests started at https://plwishmaster.stsci.edu:8081/job/RT/job/JWST-Developers-Pull-Requests/1193

[hbushouse]

Regtest results are fine. 2 benign (unrelated) failures.