ci: add vnet scale cilium pipeline stage

[QxBytes]

Reason for Change:

Adds cilium podsubnet vnet scale to the pipeline for e2e testing of cns and related components. Also updates the makefile to explicitly include pod allocation mode static block for targets that are intended to use vnet scale mode. Currently there seem to be makefile targets that are meant to create vnet scale clusters but upon creation and examination of their nncs, the mode only mentions

kubernetes.azure.com/podnetwork-subnet=podnet
kubernetes.azure.com/podnetwork-type=vnet

We expect

kubernetes.azure.com/podnetwork-subnet=podnet
kubernetes.azure.com/podnetwork-type=vnetblock

Issue Fixed:

Requirements:

• uses conventional commit messages
• includes documentation
• adds unit tests
• relevant PR labels added

Notes:
Will fail until relevant backend changes go in for creating vnet scale clusters with network plugin none