ignore replicas if HPA is set

[jmazzitelli]

part of: kiali/kiali#7559

To test this:

1. Create this file (/tmp/values.yaml) - note that HPA is defined and an abnormally large value for deployment.replicas is set - you will notice that large replicas value won't appear in the generated yaml:

deployment:
  replicas: 123456
  hpa:
    spec:
      maxReplicas: 6
      minReplicas: 3
      metrics:
      - type: Resource
        resource:
          name: cpu
          target:
            type: Utilization
            averageUtilization: 70
      - type: Resource
        resource:
          name: memory
          target:
            type: Utilization
            averageUtilization: 70
  resources:
    requests:
      memory: "1Gi"
    limits:
      memory: "2Gi"

2. Check out this PR branch and build the helm charts: make build-helm-charts
3. Show the deployment and HPA templates using that values file:

helm template -f /tmp/values.yaml --show-only templates/deployment.yaml --show-only templates/hpa.yaml  _output/charts/kiali-server-*.tgz

4. Notice that there is an HPA resource generated in the output.
5. Notice there is NO spec.replicas in the generated Deployment (notice the large value for replicas does not appear in the output):

helm template -f /tmp/values.yaml --show-only templates/deployment.yaml --show-only templates/hpa.yaml  _output/charts/kiali-server-*.tgz | grep 123456

6. Now see that setting spec.replicas still takes effect if HPA is not defined (HPA is not defined by default, so just set the replicas on the command line, no need for a values file specified on the command line for this test, and only dump the deployment template since there is no HPA template for this test):

$ helm template --set deployment.replicas=123456 --show-only templates/deployment.yaml  _output/charts/kiali-server-*.tgz | grep 123456
  replicas: 123456

[hhovsepy]

Verified, checked before and after, the issue is fixed.
Regression test on OCP cluster including the operator PR pass.