Allow to define non-default serviceAccount for the runtime-scan-job

[ruzmuh]

Is your feature request related to a problem? Please describe.
At the moment, we cannot set the serviceAccount for runtime-scan-jobs using Helm. Moreover, it always uses the default serviceAccount. This limitation doesn't allow us to use existing serviceAccounts to provide access to artifactRegistry using Workload Identity instead of keeping google service account in kubernetes secret (gcr-sa).

Describe the solution you'd like
I would like to have the ability to set the serviceAccount for runtime-scan-jobs using a Helm variable .Values.kubeclarity-runtime-scan.serviceAccount.name.
Here is an example of how it could be implemented in scanner-template-configmap.yaml:

          {{- if index .Values "kubeclarity-runtime-scan" "serviceAccount" "name"}}
          serviceAccount: {{ index .Values "kubeclarity-runtime-scan" "serviceAccount" "name" | quote} }
          {{- end}}

Describe alternatives you've considered
We can modify the kubeclarity-kubeclarity-scanner-template ConfigMap by hand, but this approach is inconvenient and error-prone. We also can

Additional context
By adding this feature, users would be able to utilize existing serviceAccounts, which is particularly useful for providing necessary permissions, such as access to artifactRegistry in GCP.