mpls: T4489: Set priority 400 for MPLS after tunnel
mpls: T4489: Set priority 400 for MPLS after tunnel

Fix worng behavior with priority with using tunnel interfaces
MPLS configuration must be applied after tunnel interfaces
as we use an addition sysctl option 'net.mpls.conf.tun0.input = 1'
which doesn't exist without tunnel interface

Change priority:
    299 protocols/mpls
    380 interfaces/tunnel
To:
    380 interfaces/tunnel
    400 protocols/mpls

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