feat(ui_localizations): Add Norwegian (NB) localization

[ovestoerholt]

Description

Adds Norwegian localization.

Checklist

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• My PR includes unit or integration tests for all changed/updated/fixed behaviors (See Contributor Guide).
• All existing and new tests are passing.
• I updated/added relevant documentation (doc comments with ///).
• The analyzer (melos run analyze) does not report any problems on my PR.
• All unit tests pass (melos run test:unit:all doesn't fail).
• I read and followed the Flutter Style Guide.
• I signed the CLA.
• I am willing to follow-up on review comments in a timely manner.

Breaking Change

Does your PR require plugin users to manually update their apps to accommodate your change?

• Yes, this is a breaking change.
• No, this is not a breaking change.

[lesnitsky]

@ovestoerholt could you please ask someone else who speaks Norwegian to proofread this PR and approve it?

[arnsteinkjellevold]

My native language is Norwegian and have proofread and can vouch for this translation.

[lesnitsky]

@ovestoerholt please also update packages/firebase_ui_localizations/lib/src/all_languages.dart so thatnb is correctly picked up

[ovestoerholt]

@lesnitsky Added 👍

[lesnitsky]

please follow the same style for imports as the rest of the languages

[ovestoerholt]

Done 👍

[lesnitsky]

error - lib/src/lang/nb.dart:6:7 - Missing concrete implementations of 'getter FirebaseUILocalizationLabels.confirmDeleteAccountAlertMessage', 'getter FirebaseUILocalizationLabels.confirmDeleteAccountAlertTitle', and 'getter FirebaseUILocalizationLabels.confirmDeleteAccountButtonLabel'. Try implementing the missing methods, or make the class abstract. - non_abstract_class_inherits_abstract_member

Seems like there are a few missing keys.

[ovestoerholt]

Strange... Will have a look 👍

[ovestoerholt]

Ok. Found new additions in main. Will update 👍

[ovestoerholt]

@lesnitsky Please try now 👍