fix dedup email messages

lib/email_messages.rb

@@ -6,12 +6,8 @@ module EmailMessages
   def find_or_create_for_account_user(account, user, subject, body)
     subject = I18n.t(:you_are_invited_to_sign_a_document) if subject.blank?
 
-    sha1 = Digest::SHA1.hexdigest({ subject:, body: }.to_json)
+    message = account.email_messages.new(author: user, subject:, body:).tap(&:validate)
 
-    message = account.email_messages.find_by(sha1:)
-
-    message ||= account.email_messages.create!(author: user, subject:, body:)
-
-    message
+    account.email_messages.find_by(sha1: message.sha1) || message.tap { |m| m.save!(validate: false) }
   end
 end