eso should not be enabled by default but it should be based on requirement

Currently, ESO (External Secrets Operator) is enabled by default in the workload-cluster values file.

https://gitlab.com/sylva-projects/sylva-core/-/blob/main/charts/sylva-units/workload-cluster.values.yaml?ref_type=heads#L353-L354

However, it should be conditionally enabled based on specific requirements. For example, ESO should only be enabled when kubevirt-manager is enabled or when explicitly required.

Additionally, sylva-ca is having below lines, which is incorrect

    depends_on:
      external-secrets-operator: true

Instead, sylva-ca should set true depend on only when external-secrets-operator itself is enabled.

cc: @tmmorin @cristian.manda