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/gpui/src/platform.rs

@@ -70,9 +70,6 @@ pub(crate) use test::*;
 #[cfg(target_os = "windows")]
 pub(crate) use windows::*;
 
-#[cfg(any(test, feature = "test-support"))]
-pub use test::TestScreenCaptureSource;
-
 #[cfg(target_os = "macos")]
 pub(crate) fn current_platform(headless: bool) -> Rc<dyn Platform> {
     Rc::new(MacPlatform::new(headless))
@@ -152,10 +149,6 @@ pub(crate) trait Platform: 'static {
         None
     }
 
-    fn screen_capture_sources(
-        &self,
-    ) -> oneshot::Receiver<Result<Vec<Box<dyn ScreenCaptureSource>>>>;
-
     fn open_window(
         &self,
         handle: AnyWindowHandle,
@@ -235,25 +228,6 @@ pub trait PlatformDisplay: Send + Sync + Debug {
     }
 }
 
-/// A source of on-screen video content that can be captured.
-pub trait ScreenCaptureSource {
-    /// Returns the video resolution of this source.
-    fn resolution(&self) -> Result<Size<Pixels>>;
-
-    /// Start capture video from this source, invoking the given callback
-    /// with each frame.
-    fn stream(
-        &self,
-        frame_callback: Box<dyn Fn(ScreenCaptureFrame)>,
-    ) -> oneshot::Receiver<Result<Box<dyn ScreenCaptureStream>>>;
-}
-
-/// A video stream captured from a screen.
-pub trait ScreenCaptureStream {}
-
-/// A frame of video captured from a screen.
-pub struct ScreenCaptureFrame(pub PlatformScreenCaptureFrame);
-
 /// An opaque identifier for a hardware display
 #[derive(PartialEq, Eq, Hash, Copy, Clone)]
 pub struct DisplayId(pub(crate) u32);