Consolidate RTP header extension validation in BaseChannel

Refactor WebRtcVideoEngine and WebRtcVoiceEngine to eliminate redundant
RTP header extension mapping and validation. This change shifts the
responsibility for verifying extension IDs and URI consistency from the
media engine level to BaseChannel.

Key changes:
* Remove ValidateRtpExtensions and its manual overlapping checks from
  WebRtcMediaEngine, as these are now centralized.
* Eliminate recv_rtp_extension_map_ and IdentifyExtensions calls from
  video and voice receive channels.
* Update media channels to filter extensions dynamically when
  requesting RTP parameters instead of maintaining a local filtered
  cache.
* Add CheckRtpExtensionValidity to BaseChannel to verify ID ranges,
  duplicates, and URI reassignment.
* Add historical_rtp_header_extensions_ to BaseChannel to track
  previously seen mappings and prevent illegal ID-to-URI reassignments
  during session renegotiation.

Bug: webrtc:42220456
Change-Id: I165e7f9af21b73d6e2ba66ee9367d140f00826eb
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/453661
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Tomas Gunnarsson <tommi@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#47086}