need to align rke2-multus chart version with RKE2 validated versions

We were recently made aware that, similarly as for calico, coredns, and ingress-nginx, we need to align rke2-multus with the versions tested with rke2.

Practically speaking this means:

• stopping renovate on this chart
• aligning version based on information from https://github.com/rancher/rke2/blob/v1.31.10%2Brke2r1/charts/chart_versions.yaml (for each RKE2 release), if needed using helm_chart_versions if the versions differ depending on the RKE2 release

/cc @dragos.gerea @loic.nicolle