Revert "build: clean up pc/BUILD.gn dependencies"

This reverts commit 4805c492a259b9cb70927f3b66d968eae8ef487f.

Reason for revert: Broke downstream build (too much removal)

Original change's description:
> build: clean up pc/BUILD.gn dependencies
>
> Also let gn_check_autofix ignore the libjingle_peerconnection_api target.
>
> done using
>   tools_webrtc/gn_check_autofix.py -r pc/BUILD.gn
> followed by
>   tools_webrtc/gn_check_autofix.py -C out/Default/
> and picking the non-controversial changes.
>
> Manually adding the test:test_main target to unit test binaries was required.
>
> Bug: webrtc:467294026
> Change-Id: Id3a4c3dc22297789b17283692d88af26af400e94
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/432621
> 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@{#46447}

Bug: webrtc:467294026
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Change-Id: I85f067ae0f444b09df5e0770467977563aacbb5c
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/433220
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Reviewed-by: Jeremy Leconte <jleconte@google.com>
Auto-Submit: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Jeremy Leconte <jleconte@google.com>
Cr-Commit-Position: refs/heads/main@{#46455}