fix: check push notification compatibility before setting up firebase

[Prithpal-Sooriya]

Explanation

Before we were initialising firebase without checking if the browser has correct setup for it. Thus causing errors logs to be made. (not breaking the app, but still producing errors).

We now do a check to ensure we can initialise firebase.

References

MetaMask/metamask-extension#26173

Changelog

@metamask/notification-services-controller

• ADDED: getPushAvailability method to check if we can use push notifications.
• CHANGED: getFirebaseMessaging() now optionally returns null. This is an internal method not exposed outside.
• CHANGED: unsubscribePushNotifications is not optional. This is internal and not exposed outside module.

Checklist

• I've updated the test suite for new or updated code as appropriate
• I've updated documentation (JSDoc, Markdown, etc.) for new or updated code as appropriate
• I've highlighted breaking changes using the "BREAKING" category above as appropriate
• I've prepared draft pull requests for clients and consumer packages to resolve any breaking changes