Reland "Passing video codec settings to lower layers"

This is a reland of
https://webrtc-review.googlesource.com/c/src/+/412641

In the previous implementation, when the codec was switched in
RequestEncoderSwitch(), there was an issue where video_format still
referred to the old codec.

By updating rtp_parameters_ in WebRtcVideoSendStream::SetCodec(),
video_format is now updated to the correct codec.

Original change's description:
> Passing video codec settings to lower layers
>
> In the CL at https://webrtc-review.googlesource.com/c/src/+/387320
> I added `SimulcastStream::video_format`, but I forgot to set this value
> in the upper layer.
>
> Bug: webrtc:362277533
> Change-Id: I16fa78e99c1998d3fbc7aca03a83e74fa8278d7d
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/412641
> Commit-Queue: Henrik Boström <hbos@webrtc.org>
> Reviewed-by: Erik Språng <sprang@webrtc.org>
> Reviewed-by: Harald Alvestrand <hta@webrtc.org>
> Reviewed-by: Henrik Boström <hbos@webrtc.org>
> Cr-Commit-Position: refs/heads/main@{#46020}

Bug: webrtc:362277533
Change-Id: I88f674f4ec98364d7c6edb3d4566748815b19084
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/427640
Reviewed-by: Henrik Boström <hbos@webrtc.org>
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Henrik Boström <hbos@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#46304}