Bug 513472

SUMMARY

When using 
```yaml
runtime: org.kde.Platform
runtime-version: 6.10
sdk: org.kde.Sdk
```
Qt doesn't work on X11 anymore:
```
juliangro@x299-workstation ~> flatpak run com.github.Murmele.Gittyup
qt.qpa.plugin: From 6.5.0, xcb-cursor0 or libxcb-cursor0 is needed to load the Qt xcb platform plugin.
qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

Available platform plugins are: eglfs, linuxfb, minimal, minimalegl, offscreen, vkkhrdisplay, vnc, wayland-brcm, wayland-egl, wayland, xcb.

juliangro@x299-workstation ~ [SIGABRT]> 
```
https://github.com/flathub/com.github.Murmele.Gittyup/blob/master/com.github.Murmele.Gittyup.yml is affected by this.

STEPS TO REPRODUCE
1. Install a Qt application such as `com.github.Murmele.Gittyup` on an X11 system.
2. Run it via `flatpak run com.github.Murmele.Gittyup` to be able to see the error message.

OBSERVED RESULT
Application fails to launch due to missing KDE runtime library.

EXPECTED RESULT
KDE runtime library should contain the library mentioned in the error message and the application should start.