remove withCleanup helper

Author: phryneas

src/profile/disableActWarnings.ts

@@ -1,15 +1,16 @@
-import { withCleanup } from "./withCleanup.js";
-
 /**
  * Temporarily disable act warnings.
  *
  * https://github.com/reactwg/react-18/discussions/102
  */
 export function disableActWarnings() {
-  const prev = { prevActEnv: (globalThis as any).IS_REACT_ACT_ENVIRONMENT };
-  (globalThis as any).IS_REACT_ACT_ENVIRONMENT = false;
+  const anyThis = globalThis as any;
+  const prevActEnv = anyThis.IS_REACT_ACT_ENVIRONMENT;
+  anyThis.IS_REACT_ACT_ENVIRONMENT = false;
 
-  return withCleanup(prev, ({ prevActEnv }) => {
-    (globalThis as any).IS_REACT_ACT_ENVIRONMENT = prevActEnv;
-  });
+  return {
+    [Symbol.dispose]() {
+      anyThis.IS_REACT_ACT_ENVIRONMENT = prevActEnv;
+    },
+  };
 }