gtk-demo: Make style apply in the file browser

Commit 5afe6f78 claims to make this demo
'look good', but it failed to actually make its
css apply. Now it really looks good.
12 jobs for matthiasc/for-master in 58 minutes and 57 seconds
Status Job ID Name Coverage
  .Pre
passed #807965
style-check-diff

00:01:51

 
  Build
passed #808038
fedora-x86_64

00:08:52

passed #807968
win32-ps
msys2-mingw64

00:15:47

passed #808037
release-build

00:07:16

failed #807966
fedora-x86_64

00:35:52

failed #807967
release-build

00:36:49

 
  Analysis
failed #807970
privileged allowed to fail
asan-build

00:13:09

passed #807969
static-scan

00:24:03

 
  Docs
passed #807971
reference

00:08:01

 
  Flatpak
manual #807972
flatpak allowed to fail manual
flatpak-manual:demo
manual #807974
flatpak allowed to fail manual
flatpak-manual:icon-browser
manual #807973
flatpak allowed to fail manual
flatpak-manual:widget-factory
 
Name Stage Failure
failed
asan-build Analysis
Processing gtk suite css:
- css: 195 total, 194 pass, 1 fail
Processing gtk suite tools:
- tools: 3 total, 3 pass, 0 fail
Processing gtk suite reftest:
- reftest: 132 total, 130 pass, 2 fail
Running after_script
Uploading artifacts for failed job
ERROR: Job failed: exit code 1