fix(react): use useLayoutEffect for hasMounted to prevent source element race condition (#1751)

Author: pyto86pri

packages/react/src/components/provider.tsx

@@ -101,7 +101,7 @@ function MediaOutlet({ provider, mediaProps, iframeProps }: MediaOutletProps) {
     });
   }, [isGoogleCast]);
 
-  React.useEffect(() => {
+  React.useLayoutEffect(() => {
     setHasMounted(true);
   }, []);