Cookie cutter CI doesn't detect lint errors in baked projects

[robrap]

A PR came in with some misordered and mis-spaced imports, and the CI checks didn't catch it.

• PR with lint error: https://github.com/openedx/edx-cookiecutters/pull/177/files#diff-3ba4f097dade34825e79a72a83de3e9cd5d69338bf3fc8ab9f015e517179270fR22
• Linter that's supposed to catch this:

  edx-cookiecutters/tests/test_cookiecutter_django_ida.py

  Line 116 in f49b8be

  sh.isort(name, check_only=True, diff=True)

Note: This ticket was originally created as a private 2U ticket in April-2022, so it is possible that this is no longer relevant.