Dismiss thread notifications when opening the thread #17907

Problem

On mobile, a notification for a thread remains in the notification shade if I open T3 Code and navigate to that thread manually instead of tapping the notification.

This leaves a stale notification for a conversation I've already read.

Expected behavior

When a thread is opened/read in the app, dismiss any system notifications associated with that thread, regardless of whether the thread was opened via the notification itself.

This is similar to WhatsApp: opening a conversation clears its corresponding notification.

Notifications for other unread threads should remain untouched.

Steps to reproduce

1. Receive a notification for a T3 Code thread.
2. Open the T3 Code mobile app directly, without tapping the notification.
3. Navigate to the thread that generated the notification.
4. Observe that the notification remains in the system notification shade.

Suggested behavior

Associate notifications with their thread/session ID and clear the matching notification(s) when that thread is opened or marked as read.