Add Language File Validation for CI/CD

[geekygirlsarah]

What GitHub issue does this PR apply to?

Resolves #453

What changed and why?

• Created a Django management command to validate the language files
• Created a GitHub action to run the above command before allowing a PR to pass

(If editing Django app) Please add screenshots

Checklist

• [x] I claimed any associated issue(s) and they are not someone else's
• [x] I have looked at documentation to ensure I made any revisions correctly
• [x] I tested my changes locally to ensure they work
• [x] (If editing Django) I have added or edited any appropriate unit tests for my changes