feat(firebase_messaging, Apple): Adds the action identifier

[Hackmodford]

Description

Adds the action identifier to the RemoteMessage object

Related Issues

closes #17315

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[MichaelVerdon]

Hey there 👋 , can you please sign the CLA?

[russellwheatley]

@Hackmodford - Considering this is Apple specific, I think it should be on this: https://github.com/Hackmodford/flutterfire/blob/feat(firebase_messaging)--Add-ios-action-identifier/packages/firebase_messaging/firebase_messaging_platform_interface/lib/src/remote_notification.dart#L69

You can update it on the notificationDict by accessing notificationDict["@notification"]["@apple"]. You will also need to sign the CLA.

[Hackmodford]

@russellwheatley I considered that, but noticed the category (which is Apple specific) is not there. So I put it next to that for consistency.

@MichaelVerdon I'm in the process of getting authorization from my company to sign the CLA.

[Hackmodford]

CLA has been signed.

[russellwheatley]

@Hackmodford - that's a fair point regarding leaving it on RemoteMessage, I'm happy to keep it there.

[russellwheatley]

Leave a note that this is a property on RemoteMessage like:

// message.actionIdentifier

Example: https://github.com/Hackmodford/flutterfire/blob/feat(firebase_messaging)--Add-ios-action-identifier/packages/firebase_messaging/firebase_messaging/ios/firebase_messaging/Sources/firebase_messaging/FLTFirebaseMessagingPlugin.m#L848