Remove invalid strings from the builtin translations
Summary:
Part of T16378
Replace them with related existing strings if possible, otherwise remove them.
Test Plan: Run the `bin/i18n validate` script from D26572 and see fewer errors.
Reviewers: O1 Blessed Committers, aklapper
Reviewed By: O1 Blessed Committers, aklapper
Subscribers: tobiaswiese, valerio.bozzolan, Matthew, Cigaryno
Differential Revision: https://we.phorge.it/D26574