T6222: VRRP show prefix for long rfc3768-compatibility interfaces

If we use rfc3768-compatibility with long interface names like
eth1.100.200 it converts the VRRP interface name name
to <interface>v<VRID><IP version>
For example eth2.100.200v10v4

The limit for interface name is 15 symbols and it causes that
interface name is ignoring by keepalived

VMAC interface name 'eth2.100.200v10v4' too long or invalid characters - ignoring
And it uses the default prefix vrrp for such cases.
It works fine, but such interfaces are not displayed in the op-mode

Allow prefix vrrp for the op-mode for show interfaces