ListItemProps.extra should be optional

components/list/Item.tsx

@@ -9,7 +9,7 @@ export interface ListItemProps {
  children?: React.ReactNode;
  prefixCls?: string;
  style?: React.CSSProperties;
  extra: React.ReactNode;
  extra?: React.ReactNode;
  actions?: Array<React.ReactNode>;
  grid?: ListGridType;
}