Revert "Use livekit's Rust SDK instead of their swift SDK (#13343)" (#20809)

Issues found:

* audio does not work well with various set-ups using USB
* switching audio during initial join may leave the client with no audio
at all
* audio streaming is done on the main thread, beachballing certain
set-ups
* worse screenshare quality (seems that there's no dynamic scaling
anymore, compared to the Swift SDK)

This reverts commit 1235d0808e.

Release Notes:

- N/A

crates/collab_ui/src/collab_panel.rs

@@ -474,10 +474,11 @@ impl CollabPanel {
                             project_id: project.id,
                             worktree_root_names: project.worktree_root_names.clone(),
                             host_user_id: participant.user.id,
-                            is_last: projects.peek().is_none() && !participant.has_video_tracks(),
+                            is_last: projects.peek().is_none()
+                                && participant.video_tracks.is_empty(),
                         });
                     }
-                    if participant.has_video_tracks() {
+                    if !participant.video_tracks.is_empty() {
                         self.entries.push(ListEntry::ParticipantScreen {
                             peer_id: Some(participant.peer_id),
                             is_last: true,