`request_uri` doesn't exist on `URI::Generic`, which is what a path is turned into. Because, y'know that would be too easy. Also: naming parts of URLs is hard.

I can get it down to this:
```
ruby
def trim_scheme_host_and_port_from_path
  uri = URI.parse(path)
  self.path = uri.request_uri if uri.respond_to?(:request_uri)
rescue URI::InvalidURIError
  # The path isn't parseable, so leave it intact for validations to report
end
```