MediaEngine: pass parameters-changed callback at construction

Refactor the parameters-changed notification mechanism by passing the
callback during the construction of media send channels rather than
setting it post-creation.

* Update MediaEngine interface and send channel factories to accept the
  absl::AnyInvocable parameters-changed callback at construction.
* Remove SetParametersChangedCallback.
* Promote OnParametersChanged to the RtpSenderInternal interface.
* Update RtpTransceiver to provide the callback and inform all senders.

Bug: webrtc:42222804
Change-Id: Ib9b2762615c73c22ca99e6051edec14a2c81b968
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/475080
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Tomas Gunnarsson <tommi@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#47828}