Support flexfec, ulpfec, and any other non-video video codecs.

[lukehb]

Relevant components:

• Signalling server
• Common library
• Frontend library
• Frontend UI library
• Matchmaker
• Platform scripts
• SFU

Problem statement:

The current code pruned the list of supported codecs to only include h.264, vpx, av1, but this meant error correction codecs like flexfec, ulpfec, and so on were removed from the browsers sdp (even though they are supported!).

Solution

This PR does not prune any codecs, but instead puts our preferred codec at the top and then adds all the other supported codecs.

Documentation

N/A

Test Plan and Compatibility

This has been tested on my machine and @gingernaz's machine and flexfec successfully is shown in the supported codecs and WebRTC stats using this PR.

This PR makes #46 redundant.

[github-actions]

💔 All backports failed

Status	Branch	Result
❌	UE5.4	Cherrypick failed because the selected commit (2750778) is empty. Did you already backport this commit?
❌	UE5.3	Cherrypick failed because the selected commit (2750778) is empty. Did you already backport this commit?
❌	UE5.2	Backport failed because of merge conflicts You might need to backport the following PRs to UE5.2: - Disable fullscreen button on IPhone as fullscreen API does not work on IPhone. - Better (?) handling of the disconnect states.
❌	UE5.5	Cherrypick failed because the selected commit (2750778) is empty. Did you already backport this commit?

Manual backport

To create the backport manually run:

backport --pr 248

Questions ?

Please refer to the Backport tool documentation and see the Github Action logs for details

[mcottontensor]

Manually cherry-picked into 5.3 and 5.4
5.5 will get merged from master.