Symptom:
interface-ID and remote-id dhcp options are not used by BNG when presented in the dhcpv6 solicit.
they are used when inserted via relay-message.

interfaceID can be used and relayed already via ddts un-30263 in XR520

Conditions:
Following BNG config:

aaa attribute format USERNAME
 format-string length 253 "%s" dhcpv6-interface-id
 !

policy-map type control subscriber IP_POLICY_BASIC
 event session-start match-first
  class type control subscriber DHCP do-until-failure
   10 activate dynamic-template IP_BASIC
   20 authorize aaa list default format USERNAME password xyz
  !
 !
 end-policy-map

if the relay forward info is present in the solicit is not used, resulting in an empty username string and the attribute is not included in the access-request