fix(disrupt_add_remove_dc): support docker backend

nemesis is changing `cassandra-rackdc.properties` for the new node
on VMs this happens before scylla starts, but on docker backend
scylla starts as the docker instance is started, so this change isn't
picked.

we are adding a restart to scylla service, so those change to
configuration would be picked

Author: fruch

sdcm/nemesis.py

@@ -4459,6 +4459,8 @@ def _add_new_node_in_new_dc(self) -> BaseNode:
                 rackdc_value = {"dc_suffix": "_nemesis_dc"}
         with new_node.remote_cassandra_rackdc_properties() as properties_file:
             properties_file.update(**rackdc_value)
+        if self.cluster.params.get('cluster_backend') == "docker":
+            new_node.restart_scylla()
         self.cluster.wait_for_init(node_list=[new_node], timeout=900,
                                    check_node_health=False)
         new_node.wait_node_fully_start()