Describe the bug
I'm unable to get push notifications working on Android. I'm guessing this is a config/setup issue, but since this issue has come up a few times I was hoping to get it working and then contribute better instructions to this repo.

To Reproduce

1. Install and configure @capacitor/push-notifications
2. Enable Cloud Messaging API in Firebase (legacy) and add the Server key to Intercom (Settings > Install > Android > Push)
3. Install and configure this plugin
4. Add app code:

   import { Intercom } from '@capacitor-community/intercom';
   import { PushNotifications } from '@capacitor/push-notifications';
   PushNotifications.requestPermissions();
   PushNotifications.register();
   Intercom.registerUnidentifiedUser();
   Intercom.displayLauncher();
   

5. Launch app > send Intercom message > close the app > reply to the message from the Intercom Inbox

Expected: Receive a push notification on the device after ~10 seconds.

Result: Nothing. The message comes through as expected if you resume the app.

Additional context

• I confirmed the device/app can receive push notifications via a manual Firebase Cloud Messaging notification to the registration token
• Push works on iOS as expected
• Confirmed the app has notification permissions enabled
• Tested on multiple devices with the app installed both via Android Studio and via Internal app sharing on the Play Store

Platforms:

• OS: Android, various devices/versions

Any help greatly appreciated!