Ensure container labels file is empty if nothing is exposed for mautrix-meta bridges

Without this, we get a warning message from Traefik:

> INF Could not create a router for the container: too many services providerName=docker

Possibly due to the multiple services defined there without a single
explicitly-defined router.

roles/custom/matrix-bridge-mautrix-meta-instagram/templates/labels.j2

@@ -4,7 +4,7 @@ SPDX-FileCopyrightText: 2024 Slavi Pantaleev
 SPDX-License-Identifier: AGPL-3.0-or-later
 #}
 
-{% if matrix_mautrix_meta_instagram_container_labels_traefik_enabled %}
+{% if matrix_mautrix_meta_instagram_container_labels_traefik_enabled and matrix_mautrix_meta_instagram_container_labels_metrics_enabled %}
 traefik.enable=true
 
 {% if matrix_mautrix_meta_instagram_container_labels_traefik_docker_network %}

roles/custom/matrix-bridge-mautrix-meta-messenger/templates/labels.j2

@@ -4,7 +4,7 @@ SPDX-FileCopyrightText: 2024 Slavi Pantaleev
 SPDX-License-Identifier: AGPL-3.0-or-later
 #}
 
-{% if matrix_mautrix_meta_messenger_container_labels_traefik_enabled %}
+{% if matrix_mautrix_meta_messenger_container_labels_traefik_enabled and matrix_mautrix_meta_messenger_container_labels_metrics_enabled %}
 traefik.enable=true
 
 {% if matrix_mautrix_meta_messenger_container_labels_traefik_docker_network %}