Remove warning for using static_dist_dir with urls

[gregjopa]

This PR removes the warning around using urls with a static dist directory. Support for this was added to lighthouse-ci in November 2019: https://github.com/GoogleChrome/lighthouse-ci/commit/93b674203a39520d40f6c985048d83d2ed46a2b8.

I set this up for my personal blog which uses Gatsby.js and ran into this warning even though everything's working fine:

It seems like this warning is unnecessary now.

Also thanks for this awesome project @alekseykulikov and Google Team 💯 It's amazing that this is all free to use.

[alekseykulikov]

Thank you @gregjopa for your kind words and such a well-documented PR ❤️

[gregjopa]

Thanks @alekseykulikov 😄