Move frame_type member from RtpDepacketizer::ParsedPayload to RTPVideoHeader

The latter is also a member of the former. This cleanup is also
a preparation for dropping WebRtcRTPHeader::frameType (or deleting
WebRtcRTPHeader right away), now that it's a video-specific member.


Tbr: kwiberg@webrtc.org # Comment change in modules/include/
Bug: None
Change-Id: I5c1f3f981f0d750713fc9b9b145278150fe32b5d
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/133024
Commit-Queue: Niels Moller <nisse@webrtc.org>
Reviewed-by: Åsa Persson <asapersson@webrtc.org>
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#27740}

modules/include/module_common_types.h

@@ -31,6 +31,7 @@ struct WebRtcRTPHeader {
 
   RTPHeader header;
   // Used for video only.
+  // TODO(nisse): Delete, now included on RTPVideoHeader.
   VideoFrameType frameType;
   // NTP time of the capture time in local timebase in milliseconds.
   int64_t ntp_time_ms;