avcfg: Fix AVOptionRanges leak

It must be freed with av_opt_freep_ranges as documented.
8 jobs for fix-leak in 15 minutes and 42 seconds
Status Name Job ID Coverage
  Preparation
passed gst indent #79163

00:00:20

passed manifest #79162

00:00:38

 
  Build
passed build fedora x86_64 #79164

00:03:18

 
  Test
passed check fedora #79165

00:03:39

 
  Full Builds
passed build android arm64 api28 #79166

00:04:34

passed build cerbero cross win32 #79168

00:07:51

passed build cerbero cross win64 #79169

00:05:40

passed build cerbero fedora x86_64 #79167

00:08:05