Return from onContextItemSelected on selecting item.

Fix:#463

Author: jainkuniya

app/src/main/java/com/zulip/android/activities/MessageListFragment.java

@@ -246,6 +246,7 @@ public boolean onContextItemSelected(MenuItem item) {
                 return true;
             case R.id.edit_message:
                 editMessage(message, adapter.getContextMenuItemSelectedPosition());
+                return true;
             case R.id.star_message:
                 starMessage(message, adapter.getContextMenuItemSelectedPosition());
                 return true;