video: fix pipeline leak in gst_video_convert_sample_async()

8 jobs for video-convert-sample-async-leak in 41 minutes and 29 seconds (queued for 1 minute and 33 seconds)
Status Job ID Name Coverage
  Preparation
passed #155634
gst indent

00:01:16

passed #155633
manifest

00:00:56

 
  Build
passed #155635
build fedora x86_64

00:04:20

 
  Test
passed #155636
check fedora

00:04:34

 
  Full Builds
passed #155637
build android arm64 api28

00:04:19

passed #155639
build cerbero cross win32

00:08:20

passed #155640
build cerbero cross win64

00:05:23

passed #155638
build cerbero fedora x86_64

00:14:44