fix: Modal close button size (#420)

Author: tiagoevanp

packages/fuselage/.loki/reference/chrome_iphone7_Containers_Modal_Modal.png

@@ -1,10 +1,7 @@
 import React from 'react';
 
-import { Button } from '../Button';
-import { Icon } from '../Icon';
+import { ActionButton } from '../Button';
 
 export const ModalClose = (props) => (
-  <Button small ghost flexShrink={0} {...props}>
-    <Icon name='cross' size='x24' />
-  </Button>
+  <ActionButton small ghost flexShrink={0} {...props} icon='cross' />
 );