Make federation self-check conditional on matrix_synapse_federation_enabled

roles/matrix-synapse/tasks/self_check_federation_api.yml

@@ -11,8 +11,14 @@
 - name: Fail if Matrix Federation API not working
   fail:
     msg: "Failed checking Matrix Federation API is up at `{{ matrix_server_fqn_matrix }}` (checked endpoint: `{{ matrix_synapse_federation_api_url_endpoint_public }}`). Is Synapse running? Is port 8448 open in your firewall? Full error: {{ result_matrix_synapse_federation_api }}"
-  when: "result_matrix_synapse_federation_api.failed or 'json' not in result_matrix_synapse_federation_api"
+  when: "matrix_synapse_federation_enabled and (result_matrix_synapse_federation_api.failed or 'json' not in result_matrix_synapse_federation_api)"
+
+- name: Fail if Matrix Federation API unexpectedly enabled
+  fail:
+      msg: "Matrix Federation API is up at `{{ matrix_server_fqn_matrix }}` (checked endpoint: `{{ matrix_synapse_federation_api_url_endpoint_public }}`) despite being disabled."
+  when: "matrix_synapse_federation_enabled == false and not result_matrix_synapse_federation_api.failed"
 
 - name: Report working Matrix Federation API
   debug:
     msg: "The Matrix Federation API at `{{ matrix_server_fqn_matrix }}` (checked endpoint: `{{ matrix_synapse_federation_api_url_endpoint_public }}`) is working"
+  when: "matrix_synapse_federation_enabled"