fix: undefined method contact in support mailbox (#2678)

if chatwoot receives an email of already existing contact with a different case say "Care@example.com", before this fix, it will throw an error. Now it will retrieve existing contact

Fixes: #2553


Co-authored-by: Sojan Jose <sojan@pepalo.com>

app/presenters/mail_presenter.rb

@@ -77,6 +77,11 @@ class MailPresenter < SimpleDelegator
     }
   end
 
+  def from
+    # changing to downcase to avoid case mismatch while finding contact
+    @mail.from.map(&:downcase)
+  end
+
   private
 
   # forcing the encoding of the content to UTF-8 so as to be compatible with database and serializers