Allow running tests without PG on unmigrated db #11204

[jacobtylerwalls]

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Description of Change

Allows running a subset of tests that don't use the database (or 0 tests in a new project).

Issues Solved

Closes #11204

Checklist

• I targeted one of these branches:
  • dev/7.6.x (under development): features, bugfixes not covered below
  • dev/7.5.x (main support): regressions, crashing bugs, security issues, major bugs in new features
  • dev/6.2.x (extended support): major security issues, data loss issues
• I added a changelog in arches/releases
• I submitted a PR to arches-docs (if appropriate)
• Unit tests pass locally with my changes
• I added tests that prove my fix is effective or that my feature works
• My test fails on the target branch

Testing instructions

• Create a project
• Change the sample test to inherit from django.test.SimpleTestCase
• Run tests

[chiatt]

Looks good!