Experiment: Target new emails.ftl file

[dschom]

This would allow us to incorporate the emails.ftl file now that emails rendering has been moved to a shared library. @bcolsson I haven't tested this yet. The PR is mostly for illustration of what I think would need to change.

[bcolsson]

Thanks for the update, I was going to say we need to preserve the auth.ftl file since there's some strings that will seemingly continue to live in ./fxa-auth-server.

Untested on my end, but I suspect this will extract the strings copied to the libs/accounts/email-renderer folder properly.

Once we have the extraction script working as intended, we'll need to sync on when to merge this PR. We'll want to ensure the following happens in the same window:

0. Make sure all strings are up to date by running old migration script and merging, then pausing syncing with Pontoon.
1. Merging this workflow change
2. Running the extract to create a PR picking up the source strings in the new library
3. Running script you mentioned in https://mozilla-hub.atlassian.net/browse/FXA-12597 to copy translations for new strings in emails.ftl from auth.ftl for all locales, (adding those changes to the PR generated in 2, or a new PR after merging 2)
4. Review and merge string PRs
5. Remove duplicate strings from fxa-auth-server / run extract script to remove duplicates from auth.ftl
6. Re-enable Pontoon sync