Notification Quick Replies appear stuck when sending (Android 8.1)

Test case

Steps

1. Set up Quasseldroid on an Android 8.1 device
   • Exact setup: LineageOS 15.1, Nexus 6
2. Connect to a core
3. Receive a private message
4. Tap the Reply option
5. Write out a message, then tap the send button
6. Wait for a few seconds

Expected

Message sends, spinner stops spinning (whether or not the notification itself dismisses is up to Android guidelines).

Actual

Message sends in the background, but the quick reply spinner continues to spin as if it's stuck. The notification must be manually updated for spinner to clear (receiving a new reply, clearing highlight status from another client, or swiping notification away).

Additional

This seems to be a regression from the switch to the AndroidX support libraries.