fix: "process" not found on local dev environment

[shibomb]

Solves #627

changes:
It also determines if the process object is undefined.

[davepagurek]

I think we still need to read the env vars in order for testing custom p5 builds to work, so I think we can't just fall back on the CDN here. I'm going to look into an alternate way to pass that data in that works with hydrated components too.

[shibomb]

@davepagurek Thank you for your response!
It works fine in my local environment with #629.
I'll close this pull request.