[SCSB-169] add user input to specify CRDS_CONTEXT

[zacharyburnett]

Resolves SCSB-169

Checklist for PR authors (skip items if you don't have permissions or they are not applicable)

• added entry in CHANGES.rst within the relevant release section
• updated or added relevant tests
• updated relevant documentation
• added relevant milestone
• added relevant label(s)
• ran regression tests, post a link to the Jenkins job below.
  How to run regression tests on a PR
• All comments are resolved
• Make sure the JIRA ticket is resolved properly

[zacharyburnett]

tested with

• https://github.com/zacharyburnett/jwst/actions/runs/10354845360
• https://github.com/zacharyburnett/jwst/actions/runs/10354846655

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 60.38%. Comparing base (f6c4095) to head (204dc8c).

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #8702   +/-   ##
=======================================
  Coverage   60.38%   60.38%           
=======================================
  Files         372      372           
  Lines       38337    38337           
=======================================
  Hits        23148    23148           
  Misses      15189    15189           

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

[braingram]

LGTM.

Once this is merged it would be helpful to trigger the ci ci_cron and tests_devdeps jobs to make sure they work work with a defined context.

[braingram]

Runs started with jwst_1255.pmap:

• ci: https://github.com/spacetelescope/jwst/actions/runs/10357731826
• ci_cron: https://github.com/spacetelescope/jwst/actions/runs/10357727841
• test_devdeps: https://github.com/spacetelescope/jwst/actions/runs/10357730367

[braingram]

All jobs picked up the 1255 context. I'm not sure why the oldestdeps just reported "This job failed" https://github.com/spacetelescope/jwst/actions/runs/10357731826/job/28670412829