fix(messaging): onNotificationOpenedApp callable return type

[Gyran]

messaging().onNotificationOpenedApp returns a function that can be used for unsubscribing from this listener
currently it's typed as returning void and you will get type errors if you try to call the returned function.

🔥

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• I read the Contributor Guide and followed the process outlined there for submitting PRs.
  • Yes
• My change supports the following platforms;
  • Android
  • iOS
• My change includes tests;
  • e2e tests added or updated in packages/\*\*/e2e
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[mikehardy]

I'm actually not sure why this method is even in the package. RNFBv6 isn't going to handle this stuff at all I don't think? No notifications in RNFBv6 @Salakar

[Gyran]

It's being called in my app when I click the notification

[Salakar]

I'm actually not sure why this method is even in the package. RNFBv6 isn't going to handle this stuff at all I don't think? No notifications in RNFBv6 @Salakar

Is a fine line on what to include and not include 😅, this allows you to at least know when a Remote Notification (FCM) causes your app to open by the user pressing it - which is something we decided you need to have really for FCM to be usable for remote notifications

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As for the change it LGTM, thanks @Gyran