Fix Fleet Kubernetes recipe and ES auth E2E failures (elastic#4944)

* Unwrap ES client error before checking for APIError

* Pin Kubernetes integration to avoid new default for k8s proxy input setting

* PR fixes

* PR fixes

config/recipes/elastic-agent/fleet-kubernetes-integration.yaml

@@ -12,7 +12,9 @@ spec:
     xpack.fleet.agents.fleet_server.hosts: ["https://fleet-server-agent-http.default.svc:8220"]
     xpack.fleet.packages:
     - name: kubernetes
-      version: latest
+      # pinning this version as the next one introduced a kube-proxy host setting default that breaks this recipe,
+      # see https://github.com/elastic/integrations/pull/1565 for more details
+      version: 0.14.0
     xpack.fleet.agentPolicies:
     - name: Default Fleet Server on ECK policy
       is_default_fleet_server: true

test/e2e/es/auth_test.go

@@ -9,6 +9,7 @@ package es
 import (
 	"bytes"
 	"context"
+	"errors"
 	"fmt"
 	"net/http"
 	"testing"
@@ -211,12 +212,12 @@ func postDocument(es esv1.Elasticsearch, k *test.K8sClient, user esclient.BasicA
 		return err
 	}
 	resp, err := esClient.Request(context.Background(), req)
-	if err != nil {
-		// the client wraps unexpected status codes in an APIError, but still returns the correct resp
-		// we want to ignore APIErrors here
-		if _, isWrappedAPIErr := err.(*esclient.APIError); !isWrappedAPIErr {
-			return err
-		}
+
+	// The client double wraps unexpected status codes in an fmt.wrapError and esclient.APIError,
+	// but still returns the correct resp. We want to ignore APIErrors here.
+	var apiError *esclient.APIError
+	if !errors.As(err, &apiError) {
+		return err
 	}
 	defer resp.Body.Close()
 	if resp.StatusCode != expectedStatusCode {