Bug 1857673

Description of problem:
The fluentd.conf was empty when enable namespaces in inputs.application

Version-Release number of selected component (if applicable):
4.6

How reproducible:
always

Steps to Reproduce:
1.  deploy CLO operator
2. create clusterlogging instance
cat << EOF | oc create -f -
apiVersion: "logging.openshift.io/v1"
kind: "ClusterLogging"
metadata:
  name: "instance"
  namespace: openshift-logging
spec:
  managementState: "Managed"
  logStore:
    type: "elasticsearch"
    elasticsearch:
      nodeCount: 1
      resources:
        limits:
          memory: 2Gi
        requests:
          cpu: 200m
          memory: 2Gi
      storage: {}
      redundancyPolicy: "ZeroRedundancy"
  visualization:
    type: "kibana"
    kibana:
      replicas: 1
  collection:
    logs:
      type: "fluentd"
      fluentd: {}
EOF
    
3. Enable namespaces in ClusterLogForwarder inputs.application
cat << EOF | oc create -f -
apiVersion: logging.openshift.io/v1
kind: ClusterLogForwarder
metadata:
  name: instance
  namespace: openshift-logging
spec:
  pipelines:
    - name: test-app
      inputRefs:
      - inputest
      outputRefs:
      - default
  inputs:
    - name: inputest
      application:
        namespaces:
        - project1
        - project2
EOF
    
4. Check the fluentd.conf
oc extract configmap/fluentd

Actual results:
The fluentd.conf is empty

Expected Result:
Only logs in the project1 and project1 are collected and sent to ES.