Room list resizes erratically when resizing the window

### Steps to reproduce

1. Resize the Element window — make it wider and then narrower again

### Outcome

#### What did you expect?

Room list remains the same size throughout.

#### What happened instead?

The room list resizes as I resize the window. This is not a problem in itself (though I personally would prefer for it to remain a constant size!) The real annoyance is that the size changes *erratically*, and so once you restore the original window size, the room list does not go back to how it looked before.

https://github.com/user-attachments/assets/88c1ed26-928b-4929-adfd-9c4cafc5275e

### Operating system

NixOS 25.11

### Browser information

Firefox 146.0.1

### URL for webapp

develop.element.io

### Application version

Element version: 9e031f887f15-js-e76f627fe332 Crypto version: Rust SDK 0.16.0 (1ac734e), Vodozemac 0.9.0

### Homeserver

Not relevant

### Will you send logs?

No