Declare VCN exposed networks as NOT_VCN_MANAGED

This change marks VCN-exposed networks as generic use, NOT_VCN_MANAGED
networks. This is the result of changes to the default NetworkCapability
set, where NOT_VCN_MANAGED was removed from the default capabilities.

Bug: 182212201
Test: atest FrameworksVcnTests
Change-Id: Iad296830201d7317537fac6bea53c79d4e41cae3
2 files changed