feat(messaging, ios): allow system to display button for in-app notification settings

[StanleyCocos]

Description

I found that there is no option to set a button to display the app settings in the notification settings when registering for push notifications. I hope to add this feature.

Specifically, the UNAuthorizationOptions.UNAuthorizationOptionProvidesAppNotificationSettings provided by iOS is missing.

Checklist

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• [x] I read the [Contributor Guide] and followed the process outlined there for submitting PRs.
• [x] 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.