Fix fullstack desktop launch (#2581)

packages/fullstack/src/launch.rs

@@ -64,7 +64,7 @@ pub fn launch(
 #[allow(unused)]
 pub fn launch(
     root: fn() -> Element,
-    contexts: Vec<Box<dyn Fn() -> Box<dyn Any> + Send + Sync>>,
+    contexts: Vec<Box<dyn Fn() -> Box<dyn Any + Send + Sync> + Send + Sync>>,
     platform_config: Config,
 ) -> ! {
     let contexts = Arc::new(contexts);