dashsink: fix double unref of sinkpad caps
no need to unref caps in gst_mpd_helper_get_XXX_codec_from_mime it will be unref in caller gst_dash_sink_get_stream_metadata()
This PR is splited from !1966 (merged)
Due to an influx of spam, we have had to impose restrictions on new accounts. Please see this wiki page for instructions on how to get full permissions. Sorry for the inconvenience.
no need to unref caps in gst_mpd_helper_get_XXX_codec_from_mime it will be unref in caller gst_dash_sink_get_stream_metadata()
This PR is splited from !1966 (merged)