fix: Consider the emails where in-reply-to header has multiple values (#7715)

- Return the first message id for now to avoid the errors and subsequently missing the message.
- Use .last instead of .first to avoid expensive query.
- Fix array response in response bot.

Fixes:  https://linear.app/chatwoot/issue/CW-2358/activerecordstatementinvalid-pgdatatypemismatch-error-argument-of-and

app/views/api/v1/conversations/partials/_conversation.json.jbuilder

@@ -17,7 +17,7 @@ json.meta do
 end
 
 json.id conversation.display_id
-if conversation.messages.where(account_id: conversation.account_id).first.blank?
+if conversation.messages.where(account_id: conversation.account_id).last.blank?
   json.messages []
 else
   json.messages [