Room message preview tool tip is unreliable

### Steps to reproduce

1. Where are you starting? What can you see?
I am looking at my room list with message previews enabled. I can see a truncated version of the message as expected.
2. What do you click?
I hover my cursor over the preview to see the full message in the form of a tool tip
3. Sometimes it renders, sometimes it does not. Web does not have this problem, on web it always renders.

### Outcome

#### What did you expect?
To consistently see the message preview expanded in a tooltip
#### What happened instead?
It _sometimes_ renders.

This is not a new bug, I have noticed for a few months, just recording it now.

### Operating system

macOS

### Application version

Element Nightly version: 2026062901 Crypto version: Rust SDK 0.18.0 (6fe03c1), Vodozemac 0.10.0

### How did you install the app?

ED repo

### Homeserver

matrix.org

### Will you send logs?

Yes