waylandsink: Avoid race condition on multi-threaded client

When waylandsink is used on some other thread than the main wayland
client thread, the waylandsink implementation is vulnerable to a

condition related to registry and surface events which handled in
seperated event queue.

The race that may happen is that after a proxy is created, but
before the queue is set, events meant to be emitted via the yet to

set queue may already have been queued on the wrong queue.

Wayland 1.11 introduced new API that allows creating a proxy
wrappper which can help to avoid this race condition.
7 jobs for wayland in 29 minutes and 47 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Preparation
passed gst indent #62704

00:00:28

passed manifest #62703

00:00:20

 
  Build
passed build fedora x86_64 #62705

00:03:21

 
  Test
passed check fedora #62758

00:15:53

failed check fedora #62706

00:17:27

 
  Full Builds
passed build android arm64 api28 #62707

00:02:54

passed build cerbero fedora x86_64 #62708

00:09:43