Remove multiline logger

[melanieclarke]

Closes #6407

This PR is a second attempt to resolve issue #6407 by removing the MultiLineLogger, based on PR #8694.

All log messages containing newlines have been removed, so this default should no longer be needed. Removing it should resolve some technical debt.

Tasks

• request a review from someone specific, to avoid making the maintainers review every PR
• add a build milestone, i.e. Build 11.3 (use the latest build if not sure)
• Does this PR change user-facing code / API?
  • add an entry to CHANGES.rst within the relevant release section (otherwise add the no-changelog-entry-needed label to this PR)
  • 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

[braingram]

Thanks!

[melanieclarke]

Regression tests started here:
https://github.com/spacetelescope/RegressionTests/actions/runs/10837423366

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 60.75%. Comparing base (418d9a8) to head (9f82b52).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #8781      +/-   ##
==========================================
- Coverage   60.76%   60.75%   -0.02%     
==========================================
  Files         375      375              
  Lines       38382    38367      -15     
==========================================
- Hits        23323    23308      -15     
  Misses      15059    15059              

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[melanieclarke]

Report generation failed for the tests I ran on GA, also the current truth files need the nightly requirements, not the last released. Running again on Jenkins:
https://plwishmaster.stsci.edu:8081/job/RT/job/JWST-Developers-Pull-Requests/1711/

[melanieclarke]

Regtest changes are all due to #8759, which was in the middle of being okified when I ran tests.

I will merge when CI is complete.