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

spec/presenters/mail_presenter_spec.rb

@@ -4,6 +4,8 @@ RSpec.describe MailPresenter do
 
   describe 'parsed mail decorator' do
     let(:mail) { create_inbound_email_from_fixture('welcome.eml').mail }
+    let(:multiple_in_reply_to_mail) { create_inbound_email_from_fixture('multiple_in_reply_to.eml').mail }
+    let(:mail_without_in_reply_to) { create_inbound_email_from_fixture('reply_cc.eml').mail }
     let(:html_mail) { create_inbound_email_from_fixture('welcome_html.eml').mail }
     let(:ascii_mail) { create_inbound_email_from_fixture('non_utf_encoded_mail.eml').mail }
     let(:decorated_mail) { described_class.new(mail) }
@@ -74,5 +76,28 @@ RSpec.describe MailPresenter do
         'أنظروا، أنا أحتاجها فقط لتقوم بالتدقيق في مقالتي الشخصية'
       )
     end
+
+    describe '#in_reply_to' do
+      context 'when "in_reply_to" is an array' do
+        it 'returns the first value from the array' do
+          mail_presenter = described_class.new(multiple_in_reply_to_mail)
+          expect(mail_presenter.in_reply_to).to eq('4e6e35f5a38b4_479f13bb90078171@small-app-01.mail')
+        end
+      end
+
+      context 'when "in_reply_to" is not an array' do
+        it 'returns the value as is' do
+          mail_presenter = described_class.new(mail)
+          expect(mail_presenter.in_reply_to).to eq('4e6e35f5a38b4_479f13bb90078178@small-app-01.mail')
+        end
+      end
+
+      context 'when "in_reply_to" is blank' do
+        it 'returns nil' do
+          mail_presenter = described_class.new(mail_without_in_reply_to)
+          expect(mail_presenter.in_reply_to).to be_nil
+        end
+      end
+    end
   end
 end