Change Mjolnir configuration to use Synapse NGINX URL. (#700)

* Change Mjolnir homeserURL to use NGINX

* Fix fmt and lint

src/synapse/workload.py

@@ -16,8 +16,6 @@
 
 from charm_state import CharmState
 
-from .api import SYNAPSE_URL
-
 SYNAPSE_CONFIG_DIR = "/data"
 
 CHECK_ALIVE_NAME = "synapse-alive"
@@ -381,8 +379,8 @@ def _get_mjolnir_config(access_token: str, room_id: str) -> typing.Dict:
     """
     with open("templates/mjolnir_production.yaml", encoding="utf-8") as mjolnir_config_file:
         config = yaml.safe_load(mjolnir_config_file)
-        config["homeserverUrl"] = SYNAPSE_URL
-        config["rawHomeserverUrl"] = SYNAPSE_URL
+        config["homeserverUrl"] = f"http://localhost:{SYNAPSE_NGINX_PORT}"
+        config["rawHomeserverUrl"] = f"http://localhost:{SYNAPSE_NGINX_PORT}"
         config["accessToken"] = access_token
         config["managementRoom"] = room_id
         return config