[flutterfire_ui] Missing label for weak password

[grlduarte]

Hello all

When attempting to register a new user with a weak password (less than 6 characters) using the Email provider the error message is not translated. May be related with #8366

In this image you can see all the fields are in Portuguese, except for the error message

The same thing happens when using Spanish

Only tested in web but I'm guessing this would happen in other platforms as well.