"STATICFILES_STORAGE/STORAGES are mutually exclusive" on Django>=4.2

[PeterJCLaw]

While #349 attempted to fix this, it appears to be fixed only where the client codebase has moved to using STORAGES. For codebases still using the legacy settings the error is still present.

Steps to reproduce:

1. Start a fresh environment
2. pip install django-configurations
3. django-admin create testing
4. Modify testing/testing/settings.py by appending:

   from configurations import Configuration
   class Config(Configuration):
      DEFAULT_FILE_STORAGE = "Whatever"

5. Modify testing/manage.py to use django-configurations, pointing at config Config created above
6. Running any testing/manage.py command, such as testing/manage.py diffsettings, will reproduce the issue

I suspect the fix could be as simple as copying the inverse of the change in #349 to detect this case, however I'm not sure if that will be sufficient.