Chore: Remove CancelablePromise (#89564)

* Remove CancelablePromise.ts as it wasn't used in anywhere

* Move cancelable-promise to the place where it is used

public/app/core/utils/CancelablePromise.ts

@@ -1,31 +0,0 @@
-// https://github.com/facebook/react/issues/5465
-
-export interface CancelablePromise<T> {
-  promise: Promise<T>;
-  cancel: () => void;
-}
-
-export interface CancelablePromiseRejection {
-  isCanceled: boolean;
-}
-
-export function isCancelablePromiseRejection(promise: unknown): promise is CancelablePromiseRejection {
-  return typeof promise === 'object' && promise !== null && 'isCanceled' in promise;
-}
-
-export const makePromiseCancelable = <T>(promise: Promise<T>): CancelablePromise<T> => {
-  let hasCanceled_ = false;
-
-  const wrappedPromise = new Promise<T>((resolve, reject) => {
-    const canceledPromiseRejection: CancelablePromiseRejection = { isCanceled: true };
-    promise.then((val) => (hasCanceled_ ? reject(canceledPromiseRejection) : resolve(val)));
-    promise.catch((error) => (hasCanceled_ ? reject(canceledPromiseRejection) : reject(error)));
-  });
-
-  return {
-    promise: wrappedPromise,
-    cancel() {
-      hasCanceled_ = true;
-    },
-  };
-};