container: Fix wrong finalize() usage

finalize must chain up to parent's finalize(), not dispose()
6 jobs for fix-chainup in 26 minutes and 31 seconds
Status Job ID Name Coverage
  Preparation
passed #69783
gst indent

00:00:22

passed #69782
manifest

00:00:22

 
  Build
passed #69784
build fedora x86_64

00:02:58

 
  Test
passed #69785
check fedora

00:15:37

 
  Full Builds
passed #69786
build android arm64 api28

00:03:47

passed #69787
build cerbero fedora x86_64

00:07:31