op mode: T4519: Show DUID instead of IAID_DUID

[nvollmar]

Change Summary

Replace IAID_DUID with DUID in op command show dhcpv6 server lease like current does.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Code style update (formatting, renaming)
• Refactoring (no functional changes)
• Migration from an old Vyatta component to vyos-1x, please link to related PR inside obsoleted component
• Other (please describe): change to command output

Related Task(s)

https://vyos.dev/T4519

Component(s) name

dhcp

Proposed changes

List DUID instead of IAID_DUID in leases overview to make adding static mappings easier.

How to test

Aquire a DHCPv6 lease and list the current leases with show dhcpv6 server lease.
Last column should be the DUID instead of IAID_DUID

Smoketest result

Couldn't really test it as I can't custom build Sagitta anymore

Checklist:

• I have read the CONTRIBUTING document
• I have linked this PR to one or more Phabricator Task(s)
• I have run the components SMOKETESTS if applicable
• My commit headlines contain a valid Task id
• My change requires a change to the documentation
• I have updated the documentation accordingly