feat(firebase_ui_localizations): Add Finnish language localization labels

[launis]

Description

This PR adds new language Finnish. The translations are checked but not reviewed by third party.

The melos run analyze noticed error on the original main and these continued to be the same when I did with my changes,

Checklist

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• [ x] All unit tests pass (melos run test:unit:all doesn't fail).
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[launis]

Thanks for the PR! Could you also get a Finnish language speaker to also approve the PR and I will get this merged. Thanks 😄

Approved by two native Finnish speakers.

[launis]

Reopened, can be closed when code changes are merged to main.