Send event to JavaScript when notification is tapped so that we navigate to the thread

Summary:
This differential brings back the second half of functionality we expect from tapping notification. When notification is tapped we start the app from intent stored in notification. CommAndroidNotificationEventEmitter listents for intents. If they come from notification, it sends parsed
version of this notification to JavaScript as an event. JavaScript uses this event to navigate to thread.

Test Plan: Build the app. Kill it. Send notification. Tap it. Ensure app opens to a thread. Repeat but without killing it - just put it into background.

Reviewers: tomek, bartek

Reviewed By: tomek

Subscribers: ashoat, atul

Differential Revision: https://phab.comm.dev/D6296