Firewall: Transport-based toggle support (1/3)

Update Connectivity with the network transports that UIDs are allowed
to use, e.g. Wi-Fi or Cellular.

Needs corresponding Connectivity and netd changes.

Co-authored-by: Tommy Webb <tommy@calyxinstitute.org>
Requires: I79342edbec92090cca20853ba50ea7fd48ec81c2
Change-Id: Ifeb8342698a8ba4ce2453d64dc32590aebca5fe5