Support optgroups for taxonomy selection list in Views

Attached patch against Drupal 10.1.x && Patch #18 Try to fix Cs issue.

Fixed cs commands

Fixed test failed issues. Please review as empty_vocabulary test checked Update preview button.

@Rassoni thanks for working on this.

That test change was not part of the patch #18 nor does it seem related to the fix in question (could be wrong).

This will need test coverage though.

Couldn't hurt to update the issue summary with the proposed solution either.

Removing credit for #22 as it's expected to check a patch before uploading and it was not documented how it no longer applied per the new policy.

Thanks!