issue with completing v8 certification projects in v9

[majestic-owl448]

I have completed the Palindrome Checker for the first time in v9, now in the settings for v8 there is written 'error displaying solution, email support@freeCodeCamp.org to get help.' because in v9 this project is not saved to database. Somewhat related to #62472 I think, as in the issue is because the same id is used for projects with a different challenge type.

[ShaunSHamilton]

My PR is related to this, and will help, but it will not resolve the issue, as some submissions have been made without the saved code. So, the "error displaying solution" should be gracefully handled - then this issue can be closed.

[c0d1ng-ma5ter]

Perhaps they should be treated as the exact same thing somehow? (URL, solution, and all of that)