[k8s] Fix show-gpus when running with incluster auth (#4452)

* Add limits only if they exist

* Fix incluster auth handling

sky/clouds/service_catalog/kubernetes_catalog.py

@@ -123,6 +123,10 @@ def _list_accelerators(
     # clusters defined by allowed_contexts.
     if region_filter is None:
         context = kubernetes_utils.get_current_kube_config_context_name()
+        if context is None and kubernetes_utils.is_incluster_config_available():
+            # If context is None and we are running in a kubernetes pod, use the
+            # in-cluster context as the current context.
+            context = kubernetes.in_cluster_context_name()
     else:
         context = region_filter
     if context is None: