in RtpVideoStreamReceiver tests set payload type for all tests packets
in RtpVideoStreamReceiver tests set payload type for all tests packets

In preparation for a change that rely on payload type beeing present.

As side effect, fix test related to RED payload type.

Bug: None
Change-Id: I42f8460fbec578184da058c1f6b9620d497d576b
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/171508
Reviewed-by: Ilya Nikolaevskiy <76788ac3efd229e9d156135d9ceb7fef65c45da4@webrtc.org>
Commit-Queue: Danil Chapovalov <55de8d9c2b5977da2dd48f967f21f9d606b172a5@webrtc.org>
Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#30864}

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