Filenames in uploads get unhelpfully truncated

### Steps to reproduce

1. Upload a file with a longish name like `gemSpec_Krypt_V2.17.0.pdf`
2. See it displayed in the timeline as:

3. feel sad (especially as there's a bunch of other different files in the room with similar names and you now have to hoverover to see which is which)

### Outcome

#### What did you expect?

don't randomly truncate the filename; cap it at the width of the timeline or something.

#### What happened instead?

arbitrary sad truncation.

### Operating system

macOS

### Browser information

chrome

### URL for webapp

develop.element.io

### Application version

Element version: 1.12.8 Crypto version: Rust SDK 0.16.0 (95b5e83), Vodozemac 0.9.0

### Homeserver

matrix.org

### Will you send logs?

No