docs(firebase_auth): Update firebase_auth.dart to add more info about the error codes

[EchoEllet]

Description

The error codes is not very clear, the way that firebase SDK handles the errors is not the best, using sealed classes or enum class is more efficient, also I found some bugs

INVALID_LOGIN_CREDENTIALS or invalid-credential: Depending on if we are using firebase emulator or the production cloud project some error codes thrown differently even though it's the exact same error

I add some important errors and not all of them, I can add more

Related Issues

There is no related issues

Checklist

Before you create this PR confirm that it meets all requirements listed below by checking the relevant checkboxes ([x]). This will ensure a smooth and quick review process. Updating the pubspec.yaml and changelogs is not required.

• [x] 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).
• [x] All existing and new tests are passing.
• [x] I updated/added relevant documentation (doc comments with ///).
• [x] The analyzer (melos run analyze) does not report any problems on my PR.
• [x] I read and followed the Flutter Style Guide.
• [x] I signed the CLA.
• [x] 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.
• [x] No, this is not a breaking change.

[EchoEllet]

The format code can be easily solved, the question is should this PR merged or rejected? in either case I still think the error handling could be improved a lot in firebase_auth

[Lyokone]

Thanks for the PR, closing in favor of https://github.com/firebase/flutterfire/pull/13100 to fix format and add error codes to platform channel