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/linux/platform.rs

@@ -35,8 +35,8 @@ use crate::{
     px, Action, AnyWindowHandle, BackgroundExecutor, ClipboardItem, CursorStyle, DisplayId,
     ForegroundExecutor, Keymap, Keystroke, LinuxDispatcher, Menu, MenuItem, Modifiers, OwnedMenu,
     PathPromptOptions, Pixels, Platform, PlatformDisplay, PlatformInputHandler, PlatformTextSystem,
-    PlatformWindow, Point, PromptLevel, Result, ScreenCaptureSource, SemanticVersion, SharedString,
-    Size, Task, WindowAppearance, WindowOptions, WindowParams,
+    PlatformWindow, Point, PromptLevel, Result, SemanticVersion, SharedString, Size, Task,
+    WindowAppearance, WindowOptions, WindowParams,
 };
 
 pub(crate) const SCROLL_LINES: f32 = 3.0;
@@ -242,14 +242,6 @@ impl<P: LinuxClient + 'static> Platform for P {
         self.displays()
     }
 
-    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> {
         self.active_window()
     }