The Visible Rooms SS list isn't correctly preloading history.

### Steps to reproduce

1. Open the app
2. Scroll down a page's worth of roomlist
3. Wait 30s or some reasonable length of time for visiblerooms to preload the history for the rooms shown
4. Open the room
5. Observe no preloaded history; instead just the most recent message + a spinner while the client calls /messages to pull in the last page of scrollback

I suspect this is because the SS Proxy's visible rooms implementation is just buggy, and will be replaced by a new /timeline API shortly, but filing this here for the sake of completeness

Separately, i've seen some situations where the room preview is stale (showing state from the room cache rather than from SS). Unsure whether that's related or not, and if there's some place where we're still relying on visible-rooms to populate room previews.

### Outcome

#### What did you expect?

Room history is preloaded for the rooms you're looking at in the room list.

#### What happened instead?

Room history is almost never preloaded.

### Your phone model

_No response_

### Operating system version

_No response_

### Application version

390

### Homeserver

_No response_

### Will you send logs?

No