Add e2e test for EgressIP pod IP leakage on secondary host interface

[arghosh93]

Tests that a new pod's real IP does not leak as source during EgressIP reconciliation when using a secondary (non-OVN) host interface.

upstream PR: ovn-kubernetes/ovn-kubernetes#6591

Summary by CodeRabbit

• Tests
  • Added a new end-to-end scenario validating EgressIP with a configured secondary network interface on BareMetal clusters running OVN-Kubernetes.
  • Creates packet-sniffing and load/stress workloads on egress nodes, deploys a node-affined trigger pod, and generates a unique identifier to correlate observed traffic.
  • Verifies packet capture includes the expected secondary EgressIP as the source, confirms the trigger pod IP is never seen as a source, and cleans up temporary resources after the run.