Remove extra checks from extract_messages

[rebecca-shoptaw]

Closes #9396.

Fix. Removes checks from the extract_messages function that are unnecessary now that the timestamp is standardized so as to catch a few more cases.

Technical

Also removed the --force-write option, as the function will now always write a new template.

Testing

1. Make a change to onscreen text in an HTML/Python file and commit -- pre-commit should fail and auto-update the messages.pot file
2. Stage the messages.pot changes and commit again -- pre-commit should pass
3. Make a change to an HTML/Python file that does not change the position or contents of on-screen text -- pre-commit should simply pass
4. Make a change that involves moving on-screen text between files or changing the name of a file with on-screen text -- pre-commit should run the same process as steps 1 & 2 even though no text has been added, changed or deleted

Screenshot

Stakeholders

@cdrini

[cdrini]

Nice! Lgtm, thank you @rebecca-shoptaw ! Not testing since your testing looks super thorough!