The litellm-helm proxy Deployment renders a pod-level securityContext from
.Values.podSecurityContext, but the Prisma migration Job rendered only the
container-level securityContext from .Values.securityContext. Clusters that
enforce pod-level admission policies (OPA Gatekeeper K8sPSPAllowedUsers, or a
PSP-style fsGroup MustRunAs rule) therefore admitted the Deployment and denied
the Job, which blocks install and upgrade because the Job runs as an ArgoCD
PreSync or Helm pre-install/pre-upgrade hook.
The Job now renders the same pod-level securityContext the Deployment does.
Charts that leave podSecurityContext unset render an empty securityContext,
matching what the Deployment already emitted, so default installs are unchanged.
Resolves LIT-4928
