Make KPO tolerant of hooks that don't have xcom methods

We probably should not be configuring xcom settings from the hook in this way but for better or worse we've done it, first in apache#26766 and again in apache#28125.

The problem is that other operators derived from KPO, e.g. GKEStartPodOperator, may use a different hook that doesn't have this xcom-specific methods.  So KPO needs to tolerate that.

airflow/providers/cncf/kubernetes/operators/pod.py

@@ -861,10 +861,16 @@ def build_pod_request_obj(self, context: Context | None = None) -> k8s.V1Pod:
             pod = secret.attach_to_pod(pod)
         if self.do_xcom_push:
             self.log.debug("Adding xcom sidecar to task %s", self.task_id)
+            sidecar_container_image = None
+            sidecar_container_resources = None
+            if hasattr(self.hook, "get_xcom_sidecar_container_image"):
+                sidecar_container_image = self.hook.get_xcom_sidecar_container_image()
+            if hasattr(self.hook, "get_xcom_sidecar_container_resources"):
+                sidecar_container_resources = self.hook.get_xcom_sidecar_container_resources()
             pod = xcom_sidecar.add_xcom_sidecar(
                 pod,
-                sidecar_container_image=self.hook.get_xcom_sidecar_container_image(),
-                sidecar_container_resources=self.hook.get_xcom_sidecar_container_resources(),
+                sidecar_container_image=sidecar_container_image,
+                sidecar_container_resources=sidecar_container_resources,
             )
 
         labels = self._get_ti_pod_labels(context)