Have libvirt-metal use bonded vlan as primary interface

What does this MR do and why?

Using the evolution for libvirt-metal introducing bonded interface, in sylva-projects/sylva-elements/container-images/libvirt-metal!42 (merged), it proposes capm3-virt envs on libvirt-metal infra use vlanif as primary interface, with a bond created out of the two VM interfaces, in active-backup bond mode, bondXmitHashPolicy: layer2 (specifically needed for for openSUSE-based deployments, but useful for Ubuntu ones also)

It also bumps s-c-c to include the fix in sylva-projects/sylva-elements/helm-charts/sylva-capi-cluster!418 (merged)), for moving past an Ubuntu OS issue described at !2153 (comment 2027409232).

Related reference(s)

Closes #989 (closed)

Test coverage