fix(ui_auth, ui_localizations): add localization label (#229)

[apnnux]

Description

Replace this paragraph with a description of what this PR is doing. If you're modifying existing behavior, describe the existing behavior, how this PR is changing it, and what motivated the change.

Related Issues

closes #229

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Breaking Change

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[russellwheatley]

Hey @apnnux - you need to follow these instruction for adding this new label here: https://github.com/firebase/FirebaseUI-Flutter/blob/main/packages/firebase_ui_localizations/README.md#adding-a-new-language

In other words, you need to update the arb files for each language and generate the code based on the arb file. Once that is done, we can look to get this Pr approved. Thanks!

[russellwheatley]

Hey @apnnux - are you going to follow up on this PR?

[apnnux]

Hi @russellwheatley yes, I'm sorry but in this moment I'm not at home, but in a few days I'll update this