Update Appliances.update override to support Python (Azure#39603)

Author: ChenxiJiang333

specification/resourceconnector/resource-manager/Microsoft.ResourceConnector/ResourceConnector/client.tsp

@@ -69,4 +69,4 @@ op AppliancesUpdateCustomized(
   @body
   tags?: Record<string>,
 ): Appliance;
-@@override(Appliances.update, AppliancesUpdateCustomized, "javascript");
+@@override(Appliances.update, AppliancesUpdateCustomized, "javascript,python");