Auto-hide conversations list when a conversation is selected

lib/ui/screens/conversations_list_screen.dart

@@ -19,9 +19,13 @@ import 'package:flutter/material.dart';
 
 class ConversationsListScreen extends StatefulWidget {
   final bool useSmallFAB;
+  final Function() onOpen;
 
-  const ConversationsListScreen({Key key, this.useSmallFAB = false})
-      : assert(useSmallFAB != null),
+  const ConversationsListScreen({
+    Key key,
+    this.useSmallFAB = false,
+    this.onOpen,
+  })  : assert(useSmallFAB != null),
         super(key: key);
 
   @override
@@ -107,6 +111,7 @@ class _ConversationScreenState extends SafeState<ConversationsListScreen> {
   /// Open a conversation
   void _openConversation(int conversationId) {
     MainController.of(context).openConversation(conversationId);
+    if (widget.onOpen != null) widget.onOpen();
   }
 
   /// Create a new conversation