webrtc: Change H264 examples to use aggregate-mode=zero-latency for best compatibility
The default changed back to none because it broke existing code. See gstreamer/gst-plugins-good#749 Part-of: <gstreamer/gst-examples!22>
The default changed back to none because it broke existing code. See gstreamer/gst-plugins-good#749 Part-of: <gstreamer/gst-examples!22>