Rooms in Android client are sporadically not updated (push seems not to work) if notifications are disabled.

*This issue was originally created by [**@MelBourbon**](https://github.com/MelBourbon) at .*

### Background information
- **Dendrite version or git SHA**: 0.11.0
- **Monolith or Polylith?**: Monolith
- **SQLite3 or Postgres?**: Postgres
- **Running in Docker?**: No
- **Client used (if applicable)**: Element Android

### Description

- **What** is the problem: Rooms with many users where notifications are disabled are not getting updated.
- **Who** is affected: Me (as I'm the only user on the server who is in rooms with more than 2 people)
- **How** is this bug manifesting: If I close Element on Android and reopen after a few hours in which I did not received a message in 1:1 chats, all rooms where notifications are disabled or limited to mentions are not up to date. Only after I receive a message in a 1:1 room (from user on same server) again all other rooms are updated again.
- **When** did this first appear: After upgrading dendrite server from 0.10.8 to 0.11.0

### Steps to reproduce
- "Close" element on Android
- Wait for a few minutes or hours
- Open element and check content in rooms without notification. You will notice that last messages seen incl. room updates or read notifications are old.
- Ask somebody (in my situation from same server) to send you a message in a 1:1 room where you have notifications enabled.
- Element is notifying you and you receive the message.
- Now open the other rooms and you will notice that messages are now up to date.