Fix interaction card test act helper

Co-Authored-By: Paperclip <noreply@paperclip.ing>

ui/src/components/IssueThreadInteractionCard.test.tsx

@@ -1,7 +1,7 @@
 // @vitest-environment jsdom
 
-import { act } from "react";
 import type { ComponentProps, ReactNode } from "react";
+import { flushSync } from "react-dom";
 import { createRoot, type Root } from "react-dom/client";
 import { afterEach, describe, expect, it, vi } from "vitest";
 import { IssueThreadInteractionCard } from "./IssueThreadInteractionCard";
@@ -34,6 +34,10 @@ vi.mock("@/lib/router", () => ({
   ),
 }));
 
+function act(callback: () => void) {
+  flushSync(callback);
+}
+
 function renderCard(
   props: Partial<ComponentProps<typeof IssueThreadInteractionCard>> = {},
 ) {