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/presenters/mail_presenter.rb

@@ -106,6 +106,15 @@ class MailPresenter < SimpleDelegator
     }
   end
 
+  def in_reply_to
+    return if @mail.in_reply_to.blank?
+
+    # Although the "in_reply_to" field in the email can potentially hold multiple values,
+    # our current system does not have the capability to handle this.
+    # FIX ME: Address this issue by returning the complete results and utilizing them for querying conversations.
+    @mail.in_reply_to.is_a?(Array) ? @mail.in_reply_to.first : @mail.in_reply_to
+  end
+
   def from
     # changing to downcase to avoid case mismatch while finding contact
     (@mail.reply_to.presence || @mail.from).map(&:downcase)

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 [