feat(messaging): add config option whether notification should be displayed in the foreground

[r0hin]

Discussed in #397

^{Originally posted by **r0hin** July 4, 2023} Using Firebase Cloud Messaging, upon receiving notification via FCM token, the notification is shown regardless of whether or not the app is in the foreground.

Is there any existing functionality to disable notifications when the app is open and instead use an in-app notification?

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Solving this problem without the use of the local notifications and directly within the capacitor-firebase/messaging package would be a cool feature!

[timmyrosen]

What is the status looking like on this? Would be great if this could be implemented soon. We have a chat app and if two people are chatting at the same time it's pretty annoying to also get a push notification on every message.

Great package otherwise, thanks for all the hard work!

[robingenz]

@timmyrosen This PR is intended to ensure that you also receive push notifications on Android in the foreground. I think you are looking for the opposite (probably for iOS).

[tomek-em]

That's what I am looking for. Any way to disable notifications when the app is in foreground on iOS.

[robingenz]

@tomek-em Got it!

What is the status looking like on this?

PRs are welcome!