TCP Health Check is not working

*Description*:
I am trying to setup a TCP health check in BackendTrafficPolicy attached to a TCPRoute, a simple echo server is running as a backend service and prints the messages. TCPRoute is working fine, able to see the message in POD when routed via eg.
However I am not seeing any messages as part of healthcheck.

*Repro steps*:
```
apiVersion: gateway.envoyproxy.io/v1alpha1
kind: BackendTrafficPolicy
metadata:
name: btp
namespace: default
spec:
targetRefs:
- group: gateway.networking.k8s.io
kind: HTTPRoute
name: backend
healthCheck:
passive:
baseEjectionTime: 1s
interval: 1s
maxEjectionPercent: 100
consecutive5XxErrors: 2
consecutiveGatewayErrors: 0
consecutiveLocalOriginFailures: 5
active:
timeout: "1s"
interval: "5s"
unhealthyThreshold: 3
healthyThreshold: 1
type: TCP
tcp: {}
```
```
apiVersion: gateway.networking.k8s.io/v1alpha2
kind: TCPRoute
metadata:
name: backend-tcp1
spec:
parentRefs:
- name: eg
namespace: default
rules:
- backendRefs:
- group: ""
kind: Service
name: backend2
namespace: default
port: 3000
```

*Environment*:
Gateway : 1.3.1
Proxy: v1.33.0