fix: migrate getToken to use FirebaseMessaging, #99

[marcjulian]

• migration used https://firebase.google.com/docs/projects/manage-installations?hl=en#retrieving-an-fcm-registration-token

This PR updates getToken for Android to use FirebaseMessaging instead of FirebaseInstallations, suggested by @sburnicki https://github.com/capacitor-community/fcm/issues/99#issuecomment-1086724322. I tested it and getToken now returns FCM Token in the same format as with the workaround proposed by @eljass https://github.com/capacitor-community/fcm/issues/99#issuecomment-942273362.

Please test this PR if it works for you too and let me know, if there is anything else todo to get this merged.

[sneko]

Hi,

@stewones could you have a look at this PR please? As mentioned in #99 the plugin is no longer working for Android which is a big breaking change when upgrading to the latest version.

Thank you,

[hembachrterran]

I tested this modification in our application, the function seems working properly. The registration token returned, except the JWT identifier. Please accept this PR and release a new version. Also there is similar problem with Capacitor Push Notification plugin @capacitor