JP-1653 changed default weighting to emsm

[jemorrison]

@drlaw1558
This should do it. I am checking on what the nightly regression test use for the CRDS context. Once we confirm it includes the new NIRSpec Cube pars reference file we will be able to merge this PR

[codecov]

Codecov Report

Merging #5277 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #5277   +/-   ##
=======================================
  Coverage   52.40%   52.40%           
=======================================
  Files         406      406           
  Lines       36480    36480           
  Branches     5645     5645           
=======================================
  Hits        19117    19117           
  Misses      16183    16183           
  Partials     1180     1180           

Flag	Coverage Δ
#unit	52.40% <ø> (ø)

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Impacted Files	Coverage Δ
jwst/cube_build/cube_build_step.py	26.21% <ø> (ø)

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[jemorrison]

@hbushouse or @stscieisenhamer
Ok for me to merge ?