gstaudio: implement SpiceAudio::disable_channel()

In case audio is turned off by user, SpiceGstaudio stops and clears
any running pipeline and stops listening to all events on Playback and
Record channels till SpiceAudio::connect_channel() is called again.

Signed-off-by: Victor Toso <victortoso@redhat.com>
Status Job ID Name Coverage
  Test
failed #2648940
fedora

00:00:12

failed #2648941
windows

00:00:12

 
Name Stage Failure
failed
windows Test
warning: redirecting to https://gitlab-ci-packet-old-dgc.freedesktop.org/victortoso/spice-common.git/
warning: redirecting to https://gitlab-ci-packet-old-dgc.freedesktop.org/victortoso/spice-common.git/
error: Server does not allow request for unadvertised object 05c0c26839e88e6d0cc5452f49c40e38543c8f97
Fetched in submodule path 'subprojects/spice-common', but it did not contain 05c0c26839e88e6d0cc5452f49c40e38543c8f97. Direct fetching of that commit failed.
Uploading artifacts...
WARNING: build-win64/meson-logs/*.txt: no matching files
WARNING: spice-protocol/build-spice-protocol/meson-logs/*.txt: no matching files
ERROR: No files to upload
ERROR: Job failed: exit code 1
failed
fedora Test
Submodule path 'subprojects/keycodemapdb': checked out 'df4e56f8fab65ba714ec18f4e7338a966a1620ad'
warning: redirecting to https://gitlab-ci-packet-new-dfs.freedesktop.org/victortoso/spice-common.git/
warning: redirecting to https://gitlab-ci-packet-new-dfs.freedesktop.org/victortoso/spice-common.git/
error: Server does not allow request for unadvertised object 05c0c26839e88e6d0cc5452f49c40e38543c8f97
Fetched in submodule path 'subprojects/spice-common', but it did not contain 05c0c26839e88e6d0cc5452f49c40e38543c8f97. Direct fetching of that commit failed.
Uploading artifacts...
WARNING: build-*/meson-logs/*.txt: no matching files
ERROR: No files to upload
ERROR: Job failed: exit code 1