Remove flushSync usage in ShadowRoot component

Replaces flushSync with a regular setState call when initializing the shadow root. This simplifies the effect and removes unnecessary synchronous state updates.

Author: martijnrusschen

src/test/helper_components/shadow_root.tsx

@@ -5,7 +5,7 @@ import React, {
   useRef,
   useState,
 } from "react";
-import { createPortal, flushSync } from "react-dom";
+import { createPortal } from "react-dom";
 
 const ShadowRoot: FC<PropsWithChildren> = ({ children }) => {
   const [shadowRoot, setShadowRoot] = useState<ShadowRoot | null>(null);
@@ -22,9 +22,7 @@ const ShadowRoot: FC<PropsWithChildren> = ({ children }) => {
     const root =
       container.shadowRoot ?? container.attachShadow({ mode: "open" });
     isInitializedRef.current = true;
-    // Use flushSync to synchronously update state within effect, avoiding cascading renders
-    // while ensuring the shadow root is available immediately for tests
-    flushSync(() => setShadowRoot(root));
+    setShadowRoot(root);
   }, []);
 
   return (