### Apache Airflow version

2.5.2

### What happened

Not sure if this is a feature not a bug, but I can use KubernetesPodOperator fine without setting a kubernetes_conn_id.
For example:
```
start = KubernetesPodOperator(
        namespace="mynamespace",
        cluster_context="mycontext",
        security_context={ 'runAsUser': 1000 },
        name="hello",
        image="busybox",
        image_pull_secrets=[k8s.V1LocalObjectReference('prodregistry')],
        cmds=["sh", "-cx"],
        arguments=["echo Start"],
        task_id="Start",
        in_cluster=False,
        is_delete_operator_pod=True,
        config_file="/home/airflow/.kube/config",
    )
```

But if I add deferrable=True to this it won't work. It seems to require an explicit kubernetes_conn_id (which we don't configure).

Is not possible to the deferrable version to work as the non deferrable one?

### What you think should happen instead

I hoped that kpo deferrable would work the same as non deferrable.

### How to reproduce

Use KPO with deferrable=True but no kubernetes_conn_id setting

### Operating System

Debian 11

### Versions of Apache Airflow Providers

_No response_

### Deployment

Official Apache Airflow Helm Chart

### Deployment details

_No response_

### Anything else

_No response_

### Are you willing to submit PR?

- [ ] Yes I am willing to submit a PR!

### Code of Conduct

- [X] I agree to follow this project's [Code of Conduct](https://github.com/apache/airflow/blob/main/CODE_OF_CONDUCT.md)

"""Add an "already checked" annotation to ensure we don't reattach on retries"""
        with _optionally_suppress(reraise=reraise):
            self.client.patch_namespaced_pod(
                name=pod.metadata.name,
                namespace=pod.metadata.namespace,
                body={"metadata": {"labels": {self.POD_CHECKED_KEY: "True"}}},
            )
    def on_kill(self) -> None:
        if self.pod:
            pod = self.pod
            kwargs = dict(
                name=pod.metadata.name,
                namespace=pod.metadata.namespace,
            )
            if self.termination_grace_period is not None:
                kwargs.update(grace_period_seconds=self.termination_grace_period)
            self.client.delete_namespaced_pod(**kwargs)
    def build_pod_request_obj(self, context: Context | None = None) -> k8s.V1Pod:
        """
        Returns V1Pod object based on pod template file, full pod spec, and other operator parameters.
        The V1Pod attributes are derived (in order of precedence) from operator params, full pod spec, pod
        template file.
        """
        self.log.debug("Creating pod for KubernetesPodOperator task %s", self.task_id)
        if self.pod_template_file:
            self.log.debug("Pod template file found, will parse for base pod")
            pod_template = pod_generator.PodGenerator.deserialize_model_file(self.pod_template_file)
            if self.full_pod_spec:
                pod_template = PodGenerator.reconcile_pods(pod_template, self.full_pod_spec)
        elif self.full_pod_spec: