Deprecate AudioEncoder::OnReceivedUplinkBandwidth

Mark AudioEncoder::OnReceivedUplinkBandwidth as deprecated in favor of
OnReceivedUplinkAllocation. The default implementation of OnReceivedUplinkBandwidth
now triggers RTC_DCHECK_NOTREACHED(). Inline default implementation of
OnReceivedUplinkAllocation forwards to OnReceivedUplinkBandwidth for backward
compatibility with external subclasses.

Bug: webrtc:442860748
Change-Id: I100b45908f9d19aa405a19b1e9dc0be26f39d84e
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/486480
Reviewed-by: Jakob Ivarsson‎ <jakobi@webrtc.org>
Reviewed-by: Erik Språng <sprang@webrtc.org>
Commit-Queue: Per Kjellander <perkj@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#48118}