obs-webrtc: Enable ice-tcp

[Sean-Der]

Description

Enable ice-tcp support in libdatachannel which is used for the WHIP/WebRTC output.

Motivation and Context

This allows streamers to publish video over UDP or TCP.

UDP is preferred for WebRTC because it gives the lowest latency. TCP is a fallback
for networks that don't allow UDP or in situations where you need 0 loss.

How Has This Been Tested?

I implemented ice-tcp against Pion. After builds are generated will ask other WebRTC
providers to test.

Types of changes

• New feature (non-breaking change which adds functionality)

Checklist:

• My code has been run through clang-format.
• I have read the contributing document.
• My code is not on the master branch.
• The code has been tested.
• All commit messages are properly formatted and commits squashed where appropriate.
• I have included updates to all appropriate documentation.

Requires: obsproject/obs-deps#305

[gxalpha]

Comment to prevent accidental merges. Please leave unresolved until the obs-deps update is removed.