JP-4192: Prepare output for extract_2d

[melanieclarke]

Partially resolves JP-4192

Update the extract_2d step to use prepare_output

Tasks

• If you have a specific reviewer in mind, tag them.
• add a build milestone, i.e. Build 12.0 (use the latest build if not sure)
• Does this PR change user-facing code / API? (if not, label with no-changelog-entry-needed)
  • write news fragment(s) in changes/: echo "changed something" > changes/<PR#>.<changetype>.rst (see changelog readme for instructions)
    • if your change breaks step-level or public API (as defined in the docs), also add a changes/<PR#>.breaking.rst news fragment
  • update or add relevant tests
  • update relevant docstrings and / or docs/ page
  • start a regression test and include a link to the running job (click here for instructions)
    • Do truth files need to be updated ("okified")?
      • after the reviewer has approved these changes, run okify_regtests to update the truth files
• if a JIRA ticket exists, make sure it is resolved properly

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 86.31%. Comparing base (bbf1e5f) to head (e2a9843).
⚠️ Report is 17 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #10157      +/-   ##
==========================================
+ Coverage   85.98%   86.31%   +0.33%     
==========================================
  Files         368      366       -2     
  Lines       38457    38435      -22     
==========================================
+ Hits        33066    33176     +110     
+ Misses       5391     5259     -132     

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[melanieclarke]

Regtests:
https://github.com/spacetelescope/RegressionTests/actions/runs/21184839415

All passing. No memory improvements because this step did not previously copy its input: it makes a new datamodel.