Revert: dhcp: T5428: always release lease from default VRF

This reverts commit 9afcea251bdc895ffd49cb11f455fd636fdf817b

A DHCP relese must also be originated from the VRF where the dhclient program is
running, else the RELEASE message can not be send through the interface towards
the DHCP server.

The reason it did not work in the past was because of https://vyos.dev/T5476