Removing the _update_user_dispatcher method from web.py as it isn't n…

…ecessary and causes the user count to reset

locust/web.py

@@ -184,10 +184,6 @@ def swarm() -> Response:
                 else:
                     self._update_shape_class(form_data_shape_class_name)
 
-                # Setting user dispatchers to None so that the runners recreate the
-                # UserDistpatcher with the appropriate user classes
-                self._reset_users_dispatcher()
-
             parsed_options_dict = vars(environment.parsed_options) if environment.parsed_options else {}
             run_time = None
             for key, value in request.form.items():
@@ -583,6 +579,3 @@ def _update_user_classes(self, user_classes):
 
     def _stop_runners(self):
         self.environment.runner.stop()
-
-    def _reset_users_dispatcher(self):
-        self.environment.runner._users_dispatcher = None