add annotation for overriding default service name generation

[SinghVikram97]

Feature

Which issue does this PR fix:
#798

What does this PR do / Why do we need it:
Adds custom annotation to override default service name generated for vpc lattice service

Testing done on this change:

{"level":"info","ts":"2025-11-20T05:11:00.012Z","caller":"test/framework.go:286","msg":"Waiting for NotFound, objects: *v1.Gateway/test-gateway, *v1.Pod/grpc-runner"}
[SynchronizedAfterSuite] PASSED [31.309 seconds]
------------------------------

Ran 131 of 131 Specs in 4549.873 seconds
SUCCESS! -- 131 Passed | 0 Failed | 0 Pending | 0 Skipped
--- PASS: TestIntegration (4549.88s)
PASS
ok      github.com/aws/aws-application-networking-k8s/test/suites/integration   4549.907s

Automation added to e2e:

Added e2e tests

Will this PR introduce any new dependencies?:

No

Will this break upgrades or downgrades. Has updating a running cluster been tested?:
No breaking changes

Does this PR introduce any user-facing change?:

Added service name override annotation `application-networking.k8s.aws/service-name-override` for HTTPRoute and GRPCRoute to customize VPC Lattice service names and avoid naming conflicts.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.