Describe the bug:
I've upgraded the installation of the Cert-Manager Chart from v1.12.4 to v1.13.0, and I've noticed the creation of an empty ConfigMap. Here is the output of the Helm Diff plugin :

+ # Source: cert-manager/charts/cert-manager/templates/controller-config.yaml
+ apiVersion: v1
+ kind: ConfigMap
+ metadata:
+   name: cert-manager
+   namespace: cert-manager
+   labels:
+     app: cert-manager
+     app.kubernetes.io/name: cert-manager
+     app.kubernetes.io/instance: cert-manager
+     app.kubernetes.io/component: "controller"
+     app.kubernetes.io/version: "v1.13.0"
+     app.kubernetes.io/managed-by: Helm
+     helm.sh/chart: cert-manager-v1.13.0
+ data:

Apparently, it is related to this commit that allowed the "ability to start controller with config file".

Expected behavior:
In my opinion, the ConfigMap should not be created if the .Values.config map is empty, which is not currently the case because the ConfigMap creation is not scoped within the {{- if .Values.config -}} block.

Moreover, we can also see this block of code in the controller-config.yaml file that checks the existence of the .Values.config.apiVersion value :

{{- if not .Values.config.apiVersion -}}
  {{- fail "config.apiVersion must be set" -}}
{{- end -}}

In my opinion, it should be replaced with required rather than fail because fail should be used to check conformity of a value, rather than existence that should be checked with required.

Or we could completely remove this check and add some abstraction by already including these two lines by default in the ConfigMap data :

config.yaml: |
    apiVersion: controller.config.cert-manager.io/v1alpha1
    kind: ControllerConfiguration
    {{ .Values.config | toYaml | nindent 4 }}

Steps to reproduce the bug:
Install the v1.13.0 Chart and let .Values.config be empty.

Anything else we need to know?:

I'd be glad to implement the PR related to this issue :)

Environment details::

• Kubernetes version: 1.25
• Cloud-provider/provisioner: GCP
• cert-manager version: 1.12.4 -> 1.13.0
• Install method: Helm

/kind bug