Set the protocol type so that PAC scripts handle ws/wss correctly

On macOS it will only allow proxies in a PAC script to use http/https
protocols, so this enables them to work by automatically setting these
as the type instead.

Change-Id: I66589057d40d135229cbae4986ef0819287ea69a
Reviewed-by: Timur Pocheptsov <timur.pocheptsov@qt.io>