Include preview cards in status entity in REST API (#9120)

* Include preview cards in status entity in REST API

* Display preview card in-stream

* Improve in-stream display of preview cards

app/javascript/mastodon/features/status/containers/card_container.js

@@ -2,7 +2,7 @@ import { connect } from 'react-redux';
 import Card from '../components/card';
 
 const mapStateToProps = (state, { statusId }) => ({
-  card: state.getIn(['cards', statusId], null),
+  card: state.getIn(['statuses', statusId, 'card'], null),
 });
 
 export default connect(mapStateToProps)(Card);