NodePoolLabelSet always use default namespace

[Links2004]

Describe the bug
we want to deploy the controller in the kube-system name, but it always use the NodePoolLabelSet from the default ns.

Steps to reproduce the issue:
config.yaml

    controller:
      namespace: kube-system
      nodepoolNameLabels:
      - nodepool.banzaicloud.io/name
      - kubernetes.io/hostname
    labeler:
      forbiddenLabelDomains:
      - google.com
      managedLabelsAnnotation: nodepool.banzaicloud.io/managed-labels
    log:
      format: logfmt
      level: debug
    healthcheck:
      listenAddress: ":8882"
      endpoint: "/healthz"

broken:

---
apiVersion: labels.banzaicloud.io/v1alpha1
kind: NodePoolLabelSet
metadata:
  name: test-host
  namespace: kube-system
spec:
  labels:
    test-label2: "test-value2"

working:

---
apiVersion: labels.banzaicloud.io/v1alpha1
kind: NodePoolLabelSet
metadata:
  name: test-host
  namespace: default
spec:
  labels:
    test-label2: "test-value2"

Expected behavior
NodePoolLabelSet is working in namespaces