fix: onWindowFocus leak

Author: Akryum

packages/app/utils/window.ts

@@ -1,7 +1,3 @@
-const windowFocusHook = createEventHook<void>()
-
-useEventListener('focus', () => {
-  windowFocusHook.trigger()
-})
-
-export const onWindowFocus = windowFocusHook.on
+export function onWindowFocus(cb: () => unknown) {
+  useEventListener('focus', cb)
+}