Change Media Devices Mid-call

[robertlong]

This PR adds the ability to change media devices mid-call using the mediaHandler.setAudioDevice and .setVideoDevice methods. Calls will automatically be renegotiated for the new media. Note that this implementation attempts to use sender.replaceTrack() which avoids renegotiation. In the case where we cannot replace the existing track, it adds a new track and renegotiates the connection.

Depends on #1972

Notes:
MediaHandler.setAudioDevice and .setVideoDevice now return a promise which can be awaited to determine if setting the new device was successful.

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Here's what your changelog entry will look like:

🚨 BREAKING CHANGES

• Change Media Devices Mid-call (#1977). Contributed by @robertlong.

[dbkr]

Looks good! How plausible would it be write a test for this?

[robertlong]

Yes, a test would be great and I can add one. I want to hold off on this longer though. I have some edits that I've made in my branch for GroupCalls and am still going over some bugs in Safari that may or may not be related.