theme: Always use Adwaita specifics as fallback

Load shared and OS specific CSS resources first and fallback to Adwaita
if no other theme specifics are found.
3 jobs for tchaik/adwaita-css-fallback in 6 minutes and 45 seconds (queued for 2 seconds)
latest
Status Job ID Name Coverage
  Test
passed #247616
flatpak

00:06:13

 
  Deploy
passed #247617
review

00:00:31

manual #247618
allowed to fail manual
stop_review