Log when a TargetBitrate XR is sent with layers enabled/disabled.
Log when a TargetBitrate XR is sent with layers enabled/disabled.

Bug: None
Change-Id: Ifecccd1ca3c8c93a22472e8993f4ba609d51f02c
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/129960
Reviewed-by: Åsa Persson <5ff7466874d1fe71d5fe7d79a8a23f5ef50662da@webrtc.org>
Commit-Queue: Rasmus Brandt <9545de3a34b925a736ae2b5ee593f3033f743a28@webrtc.org>
Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#27329}
ShiftMediaProject/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc