AL-875: Add memory saving options to compute_weight_threshold sigma_clip call

[emolter]

Resolves AL-875

This PR adds memory-saving options to a call to astropy sigma clip within compute_weight_threshold in an attempt to decrease the overall memory usage of outlier detection step (see flamegraphs on JP-3685), which cause that function to modify the input array in-place instead of copying it and allocating extra arrays for masks. Since the output sigma-clipped array is immediately collapsed into its mean, there is no need to retain it as a masked array and the behavior is unchanged.

Note that the "masked=False" option to sigma_clip does not affect that function's processing of input masked arrays, it only specifies whether the output is a masked array with clipped pixels masked, or a simple np.array with clipped pixels removed.

Tasks

• update or add relevant tests
• update relevant docstrings and / or docs/ page
• Does this PR change any API used downstream? (if not, label with no-changelog-entry-needed)
  • write news fragment(s) in changes/: echo "changed something" > changes/<PR#>.<changetype>.rst (see below for change types)
  • run regression tests with this branch installed ("git+https://github.com/<fork>/stcal@<branch>")
    • jwst regression test
    • romancal regression test

news fragment change types...

• changes/<PR#>.apichange.rst: change to public API
• changes/<PR#>.bugfix.rst: fixes an issue
• changes/<PR#>.general.rst: infrastructure or miscellaneous change

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 86.35%. Comparing base (60bd3b8) to head (22252ff).
Report is 6 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #312      +/-   ##
==========================================
+ Coverage   86.21%   86.35%   +0.14%     
==========================================
  Files          47       49       +2     
  Lines        8812     8905      +93     
==========================================
+ Hits         7597     7690      +93     
  Misses       1215     1215              

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[emolter]

I'm pretty confident this will not change anything downstream, as the unit tests for the changed function appear to be relatively robust, but I started some downstream JWST regression tests here anyway

edit: these failures are unrelated

[mairanteodoro]

Looks good to me!