Squeekboard on-screen keyboard can't input more than the first character into a textbox

**Describe the bug**

On Screen Keyboard ([raspberry-pi squeekboard](https://github.com/raspberrypi-ui/squeekboard)) cannot enter more than one character into text inputs.

**To Reproduce**
Steps to reproduce the behavior:
1. `cargo install --git https://github.com/emilk/egui.git hello_world`
2. `~/.cargo/bin/hello_world`
3. attempt to type something into the textbox using the on-screen keyboard
4. notice that input can't input more characters when there is at least one character already entered

**Expected behavior**
Input via on-screen keyboards works

**Screenshots**

https://github.com/user-attachments/assets/4e831246-da2f-4fb9-a60c-1560bfc27b2f

**Desktop:**

```
$> lsb_release -a
Distributor ID: Debian
Description: Debian GNU/Linux 12 (bookworm)
Release: 12
Codename: bookworm

$> apt list --installed squeekboard -a
Listing... Done
squeekboard/stable,now 1.21.0-1+rpt11 arm64 [installed]
squeekboard/stable 1.21.0-1 arm64
```