Chore: Refactor round robin logic (#1015)

Co-authored-by: Pranav Raj S <pranav@thoughtwoot.com>

app/workers/conversation_reply_email_worker.rb

@@ -9,7 +9,12 @@ class ConversationReplyEmailWorker
     ConversationReplyMailer.reply_with_summary(@conversation, queued_time).deliver_later
 
     # delete the redis set from the first new message on the conversation
-    conversation_mail_key = Redis::Alfred::CONVERSATION_MAILER_KEY % @conversation.id
     Redis::Alfred.delete(conversation_mail_key)
   end
+
+  private
+
+  def conversation_mail_key
+    format(::Redis::Alfred::CONVERSATION_MAILER_KEY, conversation_id: @conversation.id)
+  end
 end