Failed syncs not being reported in the UI

### Steps to reproduce

1. empirically my client can't sync, and my JS console is full of /sync timeouts.
2. i restarted the client to try to unstick it
3. it now is showing me stale messages with no indication in the UI that the content is stale.

### Outcome

#### What did you expect?

cannot connect warnings.

#### What happened instead?

nothing.

### Operating system

macOS

### Application version

_No response_

### How did you install the app?

nightly

### Homeserver

matrix.org

### Will you send logs?

Yes