feat(firebase_ui_localizations): German translation for Email verification

[fighterii]

Description

Corrected German Translations for Email Verification (which were previously not translated and just in english).

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[russellwheatley]

@fighterii - Thanks for the PR 😄. Do you have a fellow developer who is fluent in German to double check the translations, please?

[fighterii]

@russellwheatley Unfortunately not. Maybe we have to trust AI here for double-checking :D :D