fix: delete correct cluster-autoscaler HCP (#859)

**What problem does this PR solve?**:
The HCP will always be deployed in the management cluster's namespace.

**Which issue(s) this PR fixes**:
Fixes #

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Author: dkoshkin

pkg/handlers/generic/lifecycle/clusterautoscaler/strategy_helmaddon.go

@@ -77,10 +77,18 @@ func (s helmAddonStrategy) delete(
 	cluster *clusterv1.Cluster,
 	log logr.Logger,
 ) error {
+	// The cluster-autoscaler is different from other addons.
+	// It requires all resources to be created in the management cluster,
+	// which means creating the HelmChartProxy always targeting the management cluster.
+	targetCluster, err := findTargetCluster(ctx, s.client, cluster)
+	if err != nil {
+		return err
+	}
+
 	hcp := &caaphv1.HelmChartProxy{
 		ObjectMeta: metav1.ObjectMeta{
 			Name:      addonResourceNameForCluster(cluster),
-			Namespace: cluster.Namespace,
+			Namespace: targetCluster.Namespace,
 		},
 	}