Kiali operator does not preserve camel case on additional ingress labels

[gurfm]

Describe the bug

When adding additional ingress labels in the Kiali CR, such as:

apiVersion: kiali.io/v1alpha1
kind: Kiali
spec:
  deployment:
    ingress:
      additional_labels:
        camelCaseLabel: foo

the label names written in camel case are changed to snake case when propagated by the Kiali operator in the Kiali Route resource:

kind: Route
apiVersion: route.openshift.io/v1
metadata:
  name: kiali
  labels:
    camel_case_label: foo

Expected Behavior

Camel case should be preserved:

kind: Route
apiVersion: route.openshift.io/v1
metadata:
  name: kiali
  labels:
    camelCaseLabel: foo

Environment

We reproduced in Openshift 4.13 with OSSM (Maistra) 2.4 and Kiali 1.65, but from what I can see when looking at the kiali-operator code I believe all versions are impacted.

Proposed fix

Please see PR kiali/kiali-operator#741