[electrum] AppImage: Remove glib libraries from bundle to make QR scanner work

Summary:
We need to exclude the glib libraries, otherwise we can end up using
multiple incompatible versions.

We could have also included all glib libraries, but then we would have
to include the full gstreamer libraries too.

See https://github.com/AppImageCommunity/pkg2appimage/pull/500#issuecomment-1057287738

This is a backport of electroncash#2653

Test Plan: Build the AppImage, test the webcam QR code scanner on a system where it previously didn't work (Ubuntu 22.04 with an AppImage built on Debian 10)

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D14284