fix(remix-dev/cli/init): only run npm install when package.json is available

[MichaelDeBoey]

This will otherwise give the following error:

npm ERR! code ENOENT
npm ERR! syscall open
npm ERR! path .../remix.init/package.json
npm ERR! errno -2
npm ERR! enoent ENOENT: no such file or directory, open '.../remix.init/package.json'
npm ERR! enoent This is related to npm not being able to find a file.
npm ERR! enoent 

npm ERR! A complete log of this run can be found in:
npm ERR!     .../.npm/_logs/2022-05-09T22_37_36_176Z-debug.log

[kentcdodds]

Good call 👍

[github-actions]

🤖 Hello there,

We just published version v0.0.0-nightly-cbd996f-20220510 which includes this pull request. If you'd like to take it for a test run please try it out and let us know what you think!

Thanks!

[github-actions]

🤖 Hello there,

We just published version v1.5.0 which includes this pull request. If you'd like to take it for a test run please try it out and let us know what you think!

Thanks!