Do not require (but want) matrix-coturn.service in matrix-synapse

It's not really a requirement, as it can function without it.
Also, restarting matrix-coturn doesn't need to restart matrix-synapse.

roles/matrix-server/templates/systemd/matrix-synapse.service.j2

@@ -10,8 +10,7 @@ After=matrix-postgres.service
 After=matrix-goofys.service
 Requires=matrix-goofys.service
 {% endif %}
-After=matrix-coturn.service
+Wants=matrix-coturn.service
-Requires=matrix-coturn.service
 
 [Service]
 Type=simple