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

• [x] 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>")
  • [x] jwst regression test
  • [ ] romancal regression test

news fragment change types...

- ``changes/.apichange.rst``: change to public API - ``changes/.bugfix.rst``: fixes an issue - ``changes/.general.rst``: infrastructure or miscellaneous change

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

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

Additional details and impacted files

```diff @@ 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