Add custom emojis to the emoji picker (#5052)

app/javascript/mastodon/features/compose/containers/emoji_picker_dropdown_container.js

@@ -0,0 +1,8 @@
+import { connect } from 'react-redux';
+import EmojiPickerDropdown from '../components/emoji_picker_dropdown';
+
+const mapStateToProps = state => ({
+  custom_emojis: state.get('custom_emojis'),
+});
+
+export default connect(mapStateToProps)(EmojiPickerDropdown);