If Neptune concludes there is no Internet, the Downloads UI is blocked

As reported in AUTOSUITE-1038, there might be cases that Neptune is connected on the network, but there is no Internet connection on that network. Or it might be a case that the Deployment Server is on LAN only, and an Internet connectivity does it impact accessing it.

Currently, Neptune blocks the entire UI of the Downloads app if there are problems with Internet. This happens even though, the actual connection to the Deployment Server has been established.

Neptune should fail on the critical point, i.e. if a connection to the specified Deployment Server fails and report it as such and not refer to unavailable Internet connection as now.

See the discussion on AUTOSUITE-1030