Bug#1101776: thunar: Cherrypick patch to support more background image formats

[Jeremy Bícha <jeremy.bicha@canonical.com>]

Source: thunar
Version: 4.20.2-1
Severity: wishlist
Tags: trixie sid patch

Please consider cherrypicking this commit to support the popular new
image formats WebP and JPEGXL, when setting the desktop background.

https://gitlab.xfce.org/xfce/thunar/-/commit/36607763760e85

I added a hard depends in gnome-control-center to both
libjxl-gdk-pixbuf and webp-pixbuf-loader so that these image formats
would display for everyone in GNOME's background chooser.

I suggest also looking at https://bugs.debian.org/948339 . Maybe
that's unreproducible now. (I don't use Xfce myself.)

Thank you,
Jeremy Bícha