Switch fully to Rust Livekit (redux) (#27126)

Swift bindings BEGONE

Release Notes:

- Switched from using the Swift LiveKit bindings, to the Rust bindings,
fixing https://github.com/zed-industries/zed/issues/9396, a crash when
leaving a collaboration session, and making Zed easier to build.

---------

Co-authored-by: Conrad Irwin <conrad.irwin@gmail.com>
Co-authored-by: Michael Sloan <michael@zed.dev>

crates/livekit_client/src/mock_client.rs

@@ -0,0 +1,38 @@
+use crate::test;
+
+pub(crate) mod participant;
+pub(crate) mod publication;
+pub(crate) mod track;
+
+pub type RemoteVideoTrack = track::RemoteVideoTrack;
+pub type RemoteAudioTrack = track::RemoteAudioTrack;
+pub type RemoteTrackPublication = publication::RemoteTrackPublication;
+pub type RemoteParticipant = participant::RemoteParticipant;
+
+pub type LocalVideoTrack = track::LocalVideoTrack;
+pub type LocalAudioTrack = track::LocalAudioTrack;
+pub type LocalTrackPublication = publication::LocalTrackPublication;
+pub type LocalParticipant = participant::LocalParticipant;
+
+pub type Room = test::Room;
+pub use test::{ConnectionState, ParticipantIdentity, TrackSid};
+
+pub struct AudioStream {}
+
+#[cfg(not(target_os = "macos"))]
+pub type RemoteVideoFrame = std::sync::Arc<gpui::RenderImage>;
+
+#[cfg(target_os = "macos")]
+#[derive(Clone)]
+pub(crate) struct RemoteVideoFrame {}
+#[cfg(target_os = "macos")]
+impl Into<gpui::SurfaceSource> for RemoteVideoFrame {
+    fn into(self) -> gpui::SurfaceSource {
+        unimplemented!()
+    }
+}
+pub(crate) fn play_remote_video_track(
+    _track: &crate::RemoteVideoTrack,
+) -> impl futures::Stream<Item = RemoteVideoFrame> {
+    futures::stream::pending()
+}