fix(resources): fix broken ORCT Resources

Changes:
- reset timestamp for END messages

mysite/fsm/mixins.py

@@ -2,6 +2,8 @@
 import re
 from functools import partial
 
+from django.utils import timezone
+
 from ct.models import (
     Role,
     Unit,
@@ -350,6 +352,8 @@ def get_message(self, chat, current=None, message=None):
                             input_type='custom',
                             kind='message',
                             is_additional=True)[0]
+            message.timestamp = None
+            message.save()
         if self.node_name_is_one_of('GET_RESOLVE'):
                 message = Message.objects.create(
                             contenttype='unitlesson',