Update endpoint addresses in MySQL provider (#655)

Author: sinclert-canonical

src/relations/mysql_provider.py

@@ -157,6 +157,8 @@ def _update_endpoints(self, relation_id: int, remote_app: str) -> None:
             relation_id (int): The id of the relation
             remote_app (str): The name of the remote application
         """
+        self.charm.update_endpoint_addresses()
+
         try:
             rw_endpoints, ro_endpoints, _ = self.charm.get_cluster_endpoints(DB_RELATION_NAME)