Fix NeDB to Postgres importing task for matrix-bridge-appservice-irc

Postgres is not in `matrix_docker_network` anymore, so what we had
before could not possibly work anymore.

roles/custom/matrix-bridge-appservice-irc/tasks/migrate_nedb_to_postgres.yml

@@ -46,7 +46,9 @@
       --rm
       --user={{ matrix_user_uid }}:{{ matrix_user_gid }}
       --cap-drop=ALL
-      --network={{ matrix_docker_network }}
+      {% if matrix_appservice_irc_database_container_network %}
+      --network={{ matrix_appservice_irc_database_container_network }}
+      {% endif %}
       --mount type=bind,src={{ matrix_appservice_irc_data_path }},dst=/data
       --entrypoint=/bin/sh
       {{ matrix_appservice_irc_docker_image }}