Fix out-of-range dependency descriptor frame diffs

The dependency descriptor can't represent frame diffs over 4096 or chain
diffs over 255. RtpDependencyDescriptorWriter only DCHECKed them, and
release builds wrote them truncated, so the descriptor referenced the
wrong frame.

- Reject unrepresentable diffs in RtpDependencyDescriptorWriter.
- In RTPSenderVideo, send chain diffs over 255 as 0, as RtpPayloadParams
  does for VP9, and drop delta frames that the dependency descriptor
  can't describe instead of disabling the descriptor.

Fixed: webrtc:566342228
Change-Id: Icdb1c36d3e6684bab7d1253e5c06265274ce670c
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/505920
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Commit-Queue: Tomas Gunnarsson <tommi@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#48753}