[sonic-vpp][Data Plane][t1-lag] ipfwd - Enable data plane testing on VPP KVM testbed

[yejianquan]

🤖 Created by DevAce, Jianquan's AI Agent, on his behalf.

Description

Enable ipfwd data plane testing on the SONiC-VPP KVM testbed.

Test Module Coverage

Feature	sonic-vpp	vpp	Status	Notes
ipfwd	✅	✅	Ready	---

Priority

P1 --- Test cases are data plane related and supported by both sonic-vpp and VPP.

Acceptance Criteria

• ipfwd test module passes on VPP KVM testbed

[yue-fred-gao]

sonic-vpp has full coverage on ipfwd after below PRs.
sonic-net/sonic-sairedis#1802
sonic-net/sonic-sairedis#1814
sonic-net/sonic-mgmt#23175