add e2e test for locality aware load balancer

[harish2773]

What type of PR is this?
/kind feature

What this PR does / why we need it:
This PR adds an end-to-end test for Locality-Aware Load Balancing. It verifies that service traffic is correctly routed to instances in the nearest locality based on region/zone/subzone topology.

Which issue(s) this PR fixes:
Contributes towards #1146

Test Steps:

1. Namespace Setup:

   • A separate namespace (sample) is created to isolate the test environment.

2. Application Deployment:

   • Three instances of the helloworld application are deployed on different nodes to simulate locality-based traffic handling:
     • Local Instance: Deployed on ambient-worker with the version region.zone1.subzone1.
     • Remote Instance 1: Deployed on ambient-worker2 with the version region.zone1.subzone2.
     • Remote Instance 2: Deployed on ambient-worker3 with the version region.zone2.subzone3.

3. Client Setup:

   • A sleep client is deployed on ambient-worker to generate test requests.

4. Validation:

   • The test verifies the following:
     • Initially, the sleep client’s request (using curl) is handled by the local instance (region.zone1.subzone1).
     • After terminating the local instance, the test ensures that traffic shifts to the nearest available instance based on locality (either remote instance 1 or 2).

5. Cleanup:

   • All test resources (namespace, deployments, and services) are deleted after the test completes.

Does this PR introduce a user-facing change?:
NONE

[kmesh-bot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

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[kmesh-bot]

Welcome @harish2773! It looks like this is your first PR to kmesh-net/kmesh 🎉

[YaoZengzeng]

It's better to test in an existing E2E cluster ranther than creating a new Kind cluster.