sound: Don't use gtk_widget_show_all

It is removed in GTK+ 4
11 jobs for no-show-all2 in 4 minutes and 23 seconds (queued for 7 seconds)
Status Job ID Name Coverage
  Build
passed #127832
build

00:02:02

 
  Test
passed #127834
asan

00:01:36

passed #127833
test

00:01:48

 
  Manual
manual #127839
allowed to fail manual
armv8
manual #127835
allowed to fail manual
flatpak
manual #127838
allowed to fail manual
msan
manual #127840
allowed to fail manual
ppc64le
manual #127836
allowed to fail manual
tsan
manual #127837
allowed to fail manual
ubsan
 
  Review
manual #127841
allowed to fail manual
review
manual #127842
allowed to fail manual
stop_review