Previous PR #6888 broke some additional jsonnet, use {} instead of null (#6918)

Signed-off-by: Callum Styan <callumstyan@gmail.com>

Signed-off-by: Callum Styan <callumstyan@gmail.com>

production/ksonnet/loki/memberlist.libsonnet

@@ -144,6 +144,6 @@
       ) + service.mixin.spec.withClusterIp('None'),  // headless service
 
   // Disable the consul deployment if not migrating and using memberlist
-  consul_deployment: if $._config.memberlist_ring_enabled && !$._config.multikv_migration_enabled && !$._config.multikv_migration_teardown then null else super.consul_deployment,
-  consul_service: if $._config.memberlist_ring_enabled && !$._config.multikv_migration_enabled && !$._config.multikv_migration_teardown then null else super.consul_service,
+  consul_deployment: if $._config.memberlist_ring_enabled && !$._config.multikv_migration_enabled && !$._config.multikv_migration_teardown then {} else super.consul_deployment,
+  consul_service: if $._config.memberlist_ring_enabled && !$._config.multikv_migration_enabled && !$._config.multikv_migration_teardown then {} else super.consul_service,
 }