chore: Prevent notification email loop (#3386)

Configuring an agent email also as a support email inbox leads to conversations getting created in a loop if notifications were also configured to the same email.

app/mailboxes/support_mailbox.rb

@@ -7,6 +7,9 @@ class SupportMailbox < ApplicationMailbox
                     :decorate_mail
 
   def process
+    # prevent loop from chatwoot notification emails
+    return if notification_email_from_chatwoot?
+
     ActiveRecord::Base.transaction do
       find_or_create_contact
       find_or_create_conversation