[office-js-preview] (Office) Add onReadyOptions API (DefinitelyTyped#74911)

Author: alison-mk

types/office-js-preview/index.d.ts

@@ -9291,6 +9291,17 @@ declare namespace Office {
          */
         javascriptRuntimeUrl: string;
     }
+    /**
+     * Provides options related to the `onReady` event.
+     * 
+     * @beta
+     */
+    interface OnReadyOptions {
+        /**
+         * Enables the behavior that allows the `onReady` promise to be rejected.
+         */
+        setRejectionEnabled?: () => void;
+    }
     /**
      * Message used in the `onVisibilityModeChanged` invocation.
      */