[sdk][notifications] Rename NOTIFICATIONS->USER_FACING_NOTIFICATIONS and REMOTE_NOTIFICATIONS->NOTIFICATIONS
[sdk][notifications] Rename NOTIFICATIONS->USER_FACING_NOTIFICATIONS and REMOTE_NOTIFICATIONS->NOTIFICATIONS

Notification permissions are on two axes: user-facing vs. silent, and local vs. remote. On iOS, you need to ask permission to show user-facing notifications, and do not need to ask permission (but still need permission -- more on this subtlety) to send silent push notifications.

This means the primary permission developers should ask for is Permissions.USER_FACING_NOTIFICATIONS. Later we'll make it so that they need that permission and then just need to get a push token.

We'll also make it so they can get the status of Permission.REMOTE_NOTIFICATIONS but can't ask for it (or maybe asking for it will register + get the status). This matches iOS -- users can toggle the remote notification permission in Settings but they aren't prompted for it.

Since we want to free up REMOTE_NOTIFICATIONS for this behavior, we'll use "NOTIFICATIONS" to implement SDK 25's behavior of registering the token and asking for permission to show user-facing notifications.

Tested in the notifications-test app and NCL.

Fixes https://github.com/expo/universe/issues/2065

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