Remove legacy vpn types from R.array.vpn_types.

Remove the legacy vpn types from R.array.vpn_types.
Since the array of vpn types are now all allowed, the case of
using mAllowedTypes is no longer needed and removed.

Since R.array.vpn_types no longer match the constants in
VpnProfile, a conversion is needed from the VpnProfile constants
to the selected type position and vice versa.

Bug: 161776767
Test: m
Test: Flash and manual test setup VPNs
Change-Id: I76a5c940acf08c6d6adfe6ff270f39808abf88ab