splitmuxsink: do not access property variable without the object lock, use the local stack copy instead
splitmuxsink: do not access property variable without the object lock, use the local stack copy instead

sebras/gst-plugins-good,hizukiayaka/gst-plugins-good,GStreamer/gst-plugins-good,shelsonjava/gst-plugins-good,Kurento/gst-plugins-good,shelsonjava/gst-plugins-good,GrokImageCompression/gst-plugins-good,chamois94/gst-plugins-good,froggatt/gst-plugins-good-m,pexip/gst-plugins-good,rawoul/gst-plugins-good,freedesktop-unofficial-mirror/gstreamer__gst-plugins-good,vatavuserban/gst-plugins-good,shelsonjava/gst-plugins-good,stfl/gst-plugins-good,sebras/gst-plugins-good,hizukiayaka/gst-plugins-good,shelsonjava/gst-plugins-good,sebras/gst-plugins-good,stfl/gst-plugins-good,GrokImageCompression/gst-plugins-good,freedesktop-unofficial-mirror/gstreamer__gst-plugins-good,GStreamer/gst-plugins-good,freedesktop-unofficial-mirror/gstreamer__gst-plugins-good,kittee/gst-plugins-good,hizukiayaka/gst-plugins-good,GrokImageCompression/gst-plugins-good,vatavuserban/gst-plugins-good,GStreamer/gst-plugins-good,pexip/gst-plugins-good,Kurento/gst-plugins-good,ikonst/gst-plugins-good,froggatt/gst-plugins-good-m,stfl/gst-plugins-good,rawoul/gst-plugins-good,stfl/gst-plugins-good,ikonst/gst-plugins-good,vatavuserban/gst-plugins-good,froggatt/gst-plugins-good-m,StreamUtils/gst-plugins-good,pexip/gst-plugins-good,Kurento/gst-plugins-good,kittee/gst-plugins-good,pexip/gst-plugins-good,rawoul/gst-plugins-good,pexip/gst-plugins-good,sebras/gst-plugins-good,chamois94/gst-plugins-good,Kurento/gst-plugins-good,ikonst/gst-plugins-good,vatavuserban/gst-plugins-good,chamois94/gst-plugins-good,GrokImageCompression/gst-plugins-good,hizukiayaka/gst-plugins-good,ikonst/gst-plugins-good,GStreamer/gst-plugins-good,rawoul/gst-plugins-good,kittee/gst-plugins-good,froggatt/gst-plugins-good-m,StreamUtils/gst-plugins-good,kittee/gst-plugins-good,chamois94/gst-plugins-good,freedesktop-unofficial-mirror/gstreamer__gst-plugins-good,StreamUtils/gst-plugins-good,Kurento/gst-plugins-good,StreamUtils/gst-plugins-good