fixes https://github.com/spesmilo/electrum/issues/8011
> Upgraded from Appimage 4.1.5 to 4.3.2 on MX-Linux 19.
> The new version fails to start with:
>
> ```
> $ electrum
> 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, vnc, wayland-egl, wayland, wayland-xcomposite-egl, wayland-xcomposite-glx, webgl, xcb.
>
> Aborted (core dumped)
> ```
debian 10 only distributes libxcb-util0.
debian 11 distributes libxcb-util1.
our base image atm is debian 10, so we build the package from source.
34488478e6