Fix NoticeIcon tab typings for skeletonProps (#3400)

The attribute `skeletonProps` in NoticeIcon tab has default value of `{}` so it doesn't necessary have to be required as stated in typings. This PR fixes it be optional.

src/components/NoticeIcon/NoticeIconTab.d.ts

@@ -20,7 +20,7 @@ export interface INoticeIconTabProps {
   name?: string;
   showClear?: boolean;
   skeletonCount?: number;
-  skeletonProps: SkeletonProps;
+  skeletonProps?: SkeletonProps;
   style?: React.CSSProperties;
   title?: string;
 }