obey clearDynamicRtpPayloadTypes
obey clearDynamicRtpPayloadTypes

the bridge will now call this once before setting all rtp payload types
for the entire endpoint (whereas before it was called from the channel,
so each channel would clear and then add its own, meaning we'd lose the
payload types for whichever channel did that first)

jitsi/jitsi-videobridge,jitsi/jitsi-videobridge,jitsi/jitsi-videobridge,jitsi/jitsi-videobridge,jitsi/jitsi-videobridge,jitsi/jitsi-videobridge,jitsi/jitsi-videobridge