fix: Remove biz node injection for listMessage entirely

Error 479 persisted even with correct listType. The issue is that
listMessage (legacy format) does NOT need biz node injection at all.

The biz node was causing the error. listMessage works natively without it.

Changes:
- getButtonType() returns undefined for message.listMessage
- No biz node is injected for list messages
- Keep listType as PRODUCT_LIST (from previous commit)

This should allow listMessage to be delivered without error 479.

https://claude.ai/code/session_01Vgu4xrsj8aUVCHWb4pmQPF

src/Socket/messages-send.ts

@@ -628,9 +628,8 @@ export const makeMessagesSocket = (config: SocketConfig) => {
 		} else if (message.templateMessage) {
 			return 'template'
 		} else if (message.listMessage) {
-			// All listMessage types need biz node with type="product_list"
-			// This includes SINGLE_SELECT and PRODUCT_LIST
-			return 'list'
+			// listMessage works natively without biz node
+			return undefined
 		} else if (message.buttonsResponseMessage) {
 			return 'buttons_response'
 		} else if (message.listResponseMessage) {
@@ -672,9 +671,8 @@ export const makeMessagesSocket = (config: SocketConfig) => {
 			} else if (innerMessage.templateMessage) {
 				return 'template'
 			} else if (innerMessage.listMessage) {
-				// All listMessage types need biz node with type="product_list"
-				// This includes SINGLE_SELECT and PRODUCT_LIST
-				return 'list'
+				// listMessage works natively without biz node
+				return undefined
 			} else if (innerMessage.buttonsResponseMessage) {
 				return 'buttons_response'
 			} else if (innerMessage.listResponseMessage) {