bridge: T4579: remove duplicate code path already handled by base class
bridge: T4579: remove duplicate code path already handled by base class

Interface() base class already takes care about VLAN creation/removal of
newly added or no longer required interfaces. No need to code this logic again.

vyos/vyos-1x,vyos/vyos-1x,vyos/vyos-1x,vyos/vyos-1x