This change also records the VPN_DETECTED platform indication when the Mozilla VPN adapter is active. The same interface type (IF_TYPE_PROP_VIRTUAL - proprietary virtual interface) is commonly used for other VPN implementations, so this should cover more of our bases.
Additionaly we also detect this is one of the interfaces contains the string "VPN" in its FriendlyName or Description. We do this in order to detect less common VPN types.
This change means that users currently enrolled in doh-rollout that are running a VPN will not be using DoH. This is good as using DoH with a VPN might leak the user's real location by resolving domains differently. See bug 1628149 comment 27.
Differential Revision: https://phabricator.services.mozilla.com/D116463
ace4e67a15