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/windows/platform.rs

@@ -325,14 +325,6 @@ impl Platform for WindowsPlatform {
         WindowsDisplay::primary_monitor().map(|display| Rc::new(display) as Rc<dyn PlatformDisplay>)
     }
 
-    fn screen_capture_sources(
-        &self,
-    ) -> oneshot::Receiver<Result<Vec<Box<dyn ScreenCaptureSource>>>> {
-        let (mut tx, rx) = oneshot::channel();
-        tx.send(Err(anyhow!("screen capture not implemented"))).ok();
-        rx
-    }
-
     fn active_window(&self) -> Option<AnyWindowHandle> {
         let active_window_hwnd = unsafe { GetActiveWindow() };
         self.try_get_windows_inner_from_hwnd(active_window_hwnd)