T6211: Fix kea VRF op-mode commands

[davi2367]

Change summary

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):

Related Task(s)

https://vyos.dev/T6211

Related PR(s)

How to test / Smoketest result

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

[github-actions]

👍
No issues in PR Title / Commit Title

[github-actions]

CI integration 👍 passed!

Details

CI logs

• CLI Smoketests (no interfaces) 👍 passed
• CLI Smoketests VPP 👍 passed
• CLI Smoketests (interfaces only) 👍 passed
• Config tests 👍 passed
• Config tests VPP 👍 passed
• RAID1 tests 👍 passed
• TPM tests 👍 passed

[c-po]

The change itself looks reasonable. Use optional VRF argument and change order of arguments in clear_dhcp_server_lease

[dmbaturin]

The VRF argument should certainly be optional, no objections.

[sever-sever]

The lease still cannot be cleared

vyos@r14:~$ show dhcp server leases 
IP Address    MAC address        State    Lease start                Lease expiration           Remaining    Pool    Hostname    Origin
------------  -----------------  -------  -------------------------  -------------------------  -----------  ------  ----------  --------
100.64.2.10   52:54:00:96:17:74  active   2025-09-15 10:47:13+00:00  2025-09-16 10:47:13+00:00  23:57:02     LANv42  r15         local
100.64.2.11   52:54:00:09:0b:01  active   2025-09-15 10:47:28+00:00  2025-09-16 10:47:28+00:00  23:57:17     LANv42  r15         local
vyos@r14:~$ 
vyos@r14:~$ 
vyos@r14:~$ clear dhcp-server lease 100.64.2.10
Failed to clear lease for "100.64.2.10"
vyos@r14:~$ 
vyos@r14:~$ clear dhcp-server lease 100.64.2.11
Failed to clear lease for "100.64.2.11"
vyos@r14:~$ 
vyos@r14:~$ 
vyos@r14:~$ show dhcp server leases 
IP Address    MAC address        State    Lease start                Lease expiration           Remaining    Pool    Hostname    Origin
------------  -----------------  -------  -------------------------  -------------------------  -----------  ------  ----------  --------
100.64.2.10   52:54:00:96:17:74  active   2025-09-15 10:47:13+00:00  2025-09-16 10:47:13+00:00  23:56:52     LANv42  r15         local
100.64.2.11   52:54:00:09:0b:01  active   2025-09-15 10:47:28+00:00  2025-09-16 10:47:28+00:00  23:57:07     LANv42  r15         local
vyos@r14:~$