Verify FA - Turn off globally

[JohnCoene]

My console is flooded with:

This Font Awesome icon ('search') does not exist:
* if providing a custom `html_dependency` these `name` checks can 
  be deactivated with `verify_fa = FALSE`

It's available because I imported from CDN separately (maybe not the right way about it). Could the verify_fa in the fa_i function (used by shiny::icon) default to an option so we can easily turn that off globally? fa_i(..., verify_fa = getOption("htmltools.verify_fa"))