Update index.md - add profile to list engage, listID restraints

Author: samkcrespo

src/connections/destinations/catalog/actions-klaviyo/index.md

@@ -88,3 +88,7 @@ To add and remove profiles in Klaviyo with Engage Audience data:
 ### Dealing with 429 Responses from Klaviyo's API
 
 If you're encountering rate limiting issues, consider enabling batching for the Action receiving these errors. Ensure that within the mapping configuration, "Batch data to Klaviyo" is set to "Yes". This adjustment can help alleviate the rate limiting problem.
+
+### Can I send Engage Audiences to a pre-created List in Klaviyo?
+
+Please note that when using the 'Add Profile to List - Engage' Mapping, Engage audiences are designed to initiate the creation of new lists in Klaviyo, and cannot be linked to existing Klaviyo lists, making the List ID non-editable.