Fixed VCN network was not treated as internet

VCN network does not have NOT_VCN_MANAGED capability, so it
was not treated as internet. That caused data stall recovery
not able to perform when VCN is turned on.

Test: Basic testing + atest DataNetworkControllerTest
Fix: 233916204
Change-Id: I071197ca98c88cb12ada3df10679f4a059a4bc2f