Explicit External IP check in Kubernetes Discovery Plugin [CN-296] (#211

)

Import of #25324

**Original PR description:**

The problem is that it assumes the service has a type of LoadBalancer
first. If it cannot find ExternalIP there, it jumps into catch block,
assumes it has a NodePort kind, and determines ExternalIP according to
it.

The block needs to be improved in such way:
It needs to check the kind of the service, and use a specific method to
determine External IP.

Checklist:
- [x] Labels (`Team:`, `Type:`, `Source:`, `Module:`) and Milestone set
- [x] Label `Add to Release Notes` or `Not Release Notes content` set
- [x] Request reviewers if possible
- [ ] Send backports/forwardports if fix needs to be applied to
past/future releases

Imported changes:

- f63f7fa Explicit External IP check in
Kubernetes Discovery Plugin...

Closes #25324

Co-authored-by: semihbkgr <buyukgungorsemih@gmail.com>
GitOrigin-RevId: 2bb2877cfb1f876e9263616b64307ae3a1a386f8

hazelcast/src/main/java/com/hazelcast/kubernetes/KubernetesApiProvider.java

@@ -60,7 +60,10 @@ default Integer extractPort(JsonValue subsetJson) {
         }
         if (ports.size() == 1) {
             JsonValue port = ports.get(0);
-            return port.asObject().get("port").asInt();
+            JsonValue servicePort = port.asObject().get("port");
+            if (servicePort != null && servicePort.isNumber()) {
+                return servicePort.asInt();
+            }
         }
         return null;
     }