Threads: Synced threads not readable without network

### Steps to reproduce

1. Join a room with some threads
2. Open a thread: user can read messages of this thread
3. Go back to the main timeline
4. Enable airplane mode
5. The banner "Airplane mode is on" is displayed on the main timeline
6. Open the same thread than at step 2

### Outcome

#### What did you expect?

I can read the messages from the thread, they are loaded in the DB (cache).

#### What happened instead?

Empty screen, with infinite loading, restarting forever (so not really the same thing that infinite loading), looping to try to get the messages

Note that the airplane mode banner is displayed, so this is mitigating this issue.

### Your phone model

any

### Operating system version

any

### Application version and app store

1.4.16

### Homeserver

any

### Will you send logs?

No

### Are you willing to provide a PR?

No