Reland "pc: clean up pc/ dependencies"

This is a reland of commit ba2fd0ca1a4f7cb4a838a33ffa00002d668d665f
restoring the fake_sctp_transport dependency.

Original change's description:
> pc: clean up pc/ dependencies
>
> using
>   find pc/ -name BUILD.gn | xargs tools_webrtc/gn_check_autofix.py -r
> followed by
>   tools_webrtc/gn_check_autofix.py -C out/Default/
> and picking the non-controversial changes
>
> Bug: webrtc:467294026
> Change-Id: I06558ad3516a38f258a781e96e726b2cdd8c2517
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/441060
> Reviewed-by: Jeremy Leconte <jleconte@google.com>
> Reviewed-by: Harald Alvestrand <hta@webrtc.org>
> Commit-Queue: Philipp Hancke <philipp.hancke@googlemail.com>
> Cr-Commit-Position: refs/heads/main@{#46597}

Bug: webrtc:467294026
Change-Id: I019ba2c33910c38784129b2041e562e715913b27
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/440943
Reviewed-by: Jeremy Leconte <jleconte@google.com>
Commit-Queue: Philipp Hancke <philipp.hancke@googlemail.com>
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#46622}