Updated var name

group_vars/matrix_servers

@@ -2037,7 +2037,7 @@ matrix_client_cinny_self_check_validate_certificates: "{{ false if matrix_ssl_re
 
 matrix_synapse_enabled: "{{ matrix_homeserver_implementation == 'synapse' }}"
 
-matrix_synapse_container_image_self_build: "{{ matrix_architecture not in ['arm64', 'amd64'] or matrix_synapse_s3_media_store_enabled }}"
+matrix_synapse_container_image_self_build: "{{ matrix_architecture not in ['arm64', 'amd64'] or matrix_synapse_media_storage_provider_s3_enabled }}"
 
 # When ma1sd is enabled, we can use it to validate email addresses and phone numbers.
 # Synapse can validate email addresses by itself as well, but it's probably not what we want by default when we have an identity server.