linux: various fixes across the crates to make it compile

crates/live_kit_client/src/test.rs

@@ -3,7 +3,7 @@ use anyhow::{anyhow, Context, Result};
 use async_trait::async_trait;
 use collections::{BTreeMap, HashMap, HashSet};
 use futures::Stream;
-use gpui::BackgroundExecutor;
+use gpui::{BackgroundExecutor, ImageSource};
 use live_kit_server::{proto, token};
 #[cfg(target_os = "macos")]
 use media::core_video::CVImageBuffer;
@@ -846,8 +846,7 @@ impl Frame {
         self.height
     }
 
-    #[cfg(target_os = "macos")]
-    pub fn image(&self) -> CVImageBuffer {
+    pub fn image(&self) -> ImageSource {
         unimplemented!("you can't call this in test mode")
     }
 }