Allow any transport with TEST if the network is restricted

This will allow CTS to add the WIFI transport and others,
letting them test a number of essential features of the
ranking algorithm.
It's relatively safe because restricted networks can never
become the default, and NOT_RESTRICTED is a default
capability so very few apps would be affected by the shell
creating such a network.

Bug: 184037351
Test: NetworkScoreTest (which is under review)
Change-Id: I21055dc613fead6130adc2122f2cdd0af9b49adf