Make requestidlecallback work with TS 4.4 DOM (#54081)

* Make requestidlecallback work with TS 4.4 DOM

TS 4.4 improves its types for requestidlecallback. This PR makes DT match those upcoming types.

Needed after microsoft/TypeScript#44684 is merged.

* remove redundant undefined for now

types/requestidlecallback/index.d.ts

@@ -5,7 +5,7 @@
 //                 Max Boguslavskiy <https://github.com/maxbogus>
 //                 Teramoto Daiki <https://github.com/teramotodaiki>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
-// TypeScript Version: 3.0
+// TypeScript Version: 4.4
 
 /// <reference lib="dom" />
 
@@ -15,13 +15,11 @@ interface IdleDeadline {
 }
 
 interface IdleRequestOptions {
-    timeout: number;
+    timeout?: number;
 }
 
 type IdleCallbackHandle = number;
 
-type IdleRequestCallback = (deadline: IdleDeadline) => void;
-
 interface Window {
     requestIdleCallback(callback: IdleRequestCallback, options?: IdleRequestOptions): IdleCallbackHandle;
     cancelIdleCallback(handle: number): void;