fix(player_quest_srv): ignore the questLog not found error

Summary

This PR fixes the problem about the new user can't log-in to the server by stuck at /player/get_all. It caused by wrong error handling about GetLatestQuestLog. With this PR, the GetLatestQuestLog won't make RecordNotFound error anymore.

Related Issues

#97 (closed)

Changes Made

• Fix
  • internal/application/service/player_quest_service.go
    • Added nil questLog value validation
  • internal/infrastructure/persistence/user_persistence.go
    • Changed the FindUserQuestLog, it doesn't make the error at not found anymore.
      • https://gorm.io/ja_JP/docs/query.html

Testing

• Entire tutorial flows are working correctly

Checklist

• No extra unnecessary files are included.
• No extra fmt.Println() or fmt.Printf() statements are present.
• The game client can accept the response (optional)