Fix android_runtime_lock not being cfg guarded (#5244)

The `android_runtime_lock` wasn't properly `cfg` guarded in various
places, so it got included on all operating systems, not just Android by
accident. This causes deadlocks when trying to use `muda`.

packages/desktop/src/webview.rs

@@ -78,6 +78,7 @@ impl WebviewEdits {
         let response = match serde_json::from_slice(&data_from_header) {
             Ok(event) => {
                 // we need to wait for the mutex lock to let us munge the main thread..
+                #[cfg(target_os = "android")]
                 let _lock = crate::android_sync_lock::android_runtime_lock();
                 self.handle_html_event(event)
             }
@@ -557,6 +558,7 @@ impl WebviewInstance {
 
             {
                 // lock the hack-ed in lock sync wry has some thread-safety issues with event handlers and async tasks
+                #[cfg(target_os = "android")]
                 let _lock = crate::android_sync_lock::android_runtime_lock();
                 let fut = self.dom.wait_for_work();
                 pin_mut!(fut);
@@ -568,6 +570,7 @@ impl WebviewInstance {
             }
 
             // lock the hack-ed in lock sync wry has some thread-safety issues with event handlers
+            #[cfg(target_os = "android")]
             let _lock = crate::android_sync_lock::android_runtime_lock();
 
             self.edits