Block shared disks from being attached to pod VMs

[skogta]

What this PR does / why we need it:
RWX shared disks are supported only for VM service VMs. So if someone tries to attach such a volume to a pod VM, CSI driver should fail that request.

Testing done:
Created an RWX PVC with block volume mode and attached it to a pod. The pod did not come to running and it had the expected error on describing it:

Name:             pod1
Namespace:        test
Priority:         0
Service Account:  default
Node:             lvn-dvm-10-161-214-178.dvm.lvn.broadcom.net/
Labels:           <none>
Annotations:      vmware-system-image-references: {"test-container":"busybox-f462ad8139900f32e74c30158195dda0e3d9ec8e-v61241"}
Status:           Pending
IP:               
IPs:              <none>
Containers:
  test-container:
    Image:      gcr.io/google_containers/busybox:1.24
    Port:       <none>
    Host Port:  <none>
    Command:
      /bin/sh
      -c
      echo 'Hello! This is Pod1' >> /mnt/volume1/index.html && while true ; do sleep 2 ; done
    Environment:  <none>
    Mounts:
      /mnt/volume1 from test-volume (rw)
      /var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-7p9fr (ro)
Conditions:
  Type           Status
  PodScheduled   True 
Volumes:
  test-volume:
    Type:       PersistentVolumeClaim (a reference to a PersistentVolumeClaim in the same namespace)
    ClaimName:  rwx-pvc-block
    ReadOnly:   false
  kube-api-access-7p9fr:
    Type:                    Projected (a volume that contains injected data from multiple sources)
    TokenExpirationSeconds:  3607
    ConfigMapName:           kube-root-ca.crt
    ConfigMapOptional:       <nil>
    DownwardAPI:             true
QoS Class:                   BestEffort
Node-Selectors:              <none>
Tolerations:                 node.kubernetes.io/not-ready:NoExecute op=Exists for 300s
                             node.kubernetes.io/unreachable:NoExecute op=Exists for 300s
Events:
  Type     Reason              Age               From                     Message
  ----     ------              ----              ----                     -------
  Normal   Scheduled           12s               default-scheduler        Successfully assigned test/pod1 to lvn-dvm-10-161-214-178.dvm.lvn.broadcom.net
  Normal   Image               12s               image-controller         Image busybox-f462ad8139900f32e74c30158195dda0e3d9ec8e-v61241 bound successfully
  Warning  FailedAttachVolume  1s (x5 over 11s)  attachdetach-controller  AttachVolume.Attach failed for volume "pvc-464dd9eb-85ca-4a67-b070-d70d510dbd1d" : rpc error: code = Unknown desc = Shared disks are not supportd for PodVMs. Invalid request {VolumeId:f71edf26-8d20-4f95-8e76-4727255426be NodeId:lvn-dvm-10-161-214-178.dvm.lvn.broadcom.net VolumeCapability:block:<> access_mode:<mode:MULTI_NODE_MULTI_WRITER >  Readonly:false Secrets:map[] VolumeContext:map[storage.kubernetes.io/csiProvisionerIdentity:1750324078186-4714-csi.vsphere.vmware.com type:vSphere CNS Block Volume] XXX_NoUnkeyedLiteral:{} XXX_unrecognized:[] XXX_sizecache:0}

Also created RWO volume with volumemode as block and RWO volume with no volumemode provided. They were both able to attach to the pod sucessfully.

[k8s-ci-robot]

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This pull-request has been approved by: skogta
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[k8s-ci-robot]

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