If a user clones a prototype and doesnt run npm install, it won't work

[joelanman]

In v12 we used to have a check if node_modules was missing and a message telling users what to do, in v13 we don't. The most common way to not have node_modules is if you clone an existing prototype.

Possible solution:

• Provide fallback for people who haven't installed npm modules. #1918