kubernetes: pin the RetryOnFailure strategy on the Proxmox csi release #4731

packages/apps/kubernetes/templates/helmreleases/csi-proxmox.yaml sets strategy.name: RetryOnFailure on install and upgrade, like csi.yaml and cilium.yaml, but only the KubeVirt pair is pinned (cilium_install_retry_test.yaml, csi_install_retry_test.yaml). Nothing reads the Proxmox one today, because the e2e HelmRelease guard runs only on the KubeVirt substrate. So this is a gap to close before the Proxmox suite starts reusing that guard, not a live defect. A case in substrate_proxmox_addons_test.yaml asserting the strategy on both actions is enough.