Use new RtpHeaderExtensionCapability constructors

Use constructors that omit preferred_id where it is
not needed (tests) or represents 0/unset ID.
Update wrappers and PeerConnectionFactory to handle
capabilities without preferred IDs.
Remove old ToRtpCapabilities overload.

Bug: webrtc:514817938
Change-Id: Iced03d2071b99e6bf094f5bf566d8bd2eee72bbc
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/478920
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Auto-Submit: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Harald Alvestrand <hta@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#47926}