Describe the bug

When passing a theme that does not exist in query params (theme=...), I get the following error:

500: INTERNAL_SERVER_ERROR
Code: FUNCTION_INVOCATION_FAILED
ID: fra1::hrdcg-1762421377288-2993a3767f96

Expected behavior

I'd like to have the default theme as a fallback.

Screenshots / Live demo link

https://github-readme-stats.vercel.app/api?username=mikyll&show_icons=not&theme=foobar

Additional context

I noticed this some day ago, so I think this bug was mistakenly introduced with most recent commits