Enable federation API labels if the federation port is enabled

`matrix_synapse_federation_port_enabled` is defined like this:

```
matrix_synapse_federation_port_enabled: "{{ matrix_synapse_federation_enabled or matrix_synapse_federation_port_openid_resource_required }}"
```

Previously, people that disabled federation, but needed the `openid`
listener were running without these federation-related labels.

In this patch, we're also dropping the `not matrix_synapse_workers_enabled` condition,
because.. none of the Matrix-related labels would be applied anyway when
workers are enabled, thanks to `matrix_synapse_container_labels_matrix_related_labels_enabled`.

Fixes #3127

roles/custom/matrix-synapse/defaults/main.yml

@@ -253,7 +253,7 @@ matrix_synapse_container_labels_public_client_synapse_admin_api_traefik_tls_cert
 # Controls whether labels will be added that expose the Server-Server API (Federation API).
 # Regardless of whether this is enabled, it may or may not take effect due to the value of other variables.
 # See `matrix_synapse_container_labels_traefik_enabled` or `matrix_synapse_container_labels_matrix_related_labels_enabled`
-matrix_synapse_container_labels_public_federation_api_enabled: "{{ matrix_synapse_federation_enabled and matrix_synapse_federation_port_enabled and not matrix_synapse_workers_enabled }}"
+matrix_synapse_container_labels_public_federation_api_enabled: "{{ matrix_synapse_federation_port_enabled }}"
 matrix_synapse_container_labels_public_federation_api_traefik_hostname: "{{ matrix_synapse_container_labels_traefik_hostname }}"
 matrix_synapse_container_labels_public_federation_api_traefik_path_prefix: /_matrix
 matrix_synapse_container_labels_public_federation_api_traefik_rule: "Host(`{{ matrix_synapse_container_labels_public_federation_api_traefik_hostname }}`) && PathPrefix(`{{ matrix_synapse_container_labels_public_federation_api_traefik_path_prefix }}`)"