Fix staging / unmounting volume operations on Windows

[torredil]

Is this a bug fix or adding new feature?

• Bug fix.

What is this PR about?

This PR fixes several bugs uncovered by running the external e2e tests on Windows. It will allow us to run the tests in parallel and should land before #1521.

• GetDeviceNameFromMount now returns the disk number for a mount path on Windows.
• Cleanup the stage path via Rmdir in proxyMounter.Unmount() before offlining the disk.
• Remove unnecessary call to proxyMounter.WriteVolumeCache() when unpublishing a volume from the node.
• Return a nil error in GetDeviceNameFromMount if the target path does not exist, per the CSI spec: If the volume corresponding to the volume_id is not staged to the staging_target_path, the Plugin MUST reply 0 OK.

Why do we need it?

To fix the following issues:

I0308 16:30:11.616491    6048 node.go:260] "NodeUnStageVolume: volume operation finished" volumeID="vol-0575b28e63a6f11a5"
I0308 16:30:11.616491    6048 inflight.go:74] "Node Service: volume operation finished" key="vol-0575b28e63a6f11a5"
E0308 16:30:11.616491    6048 driver.go:120] "GRPC error" err=<
	rpc error: code = Internal desc = failed to check if volume is mounted: error getting device name from mount: rpc error: code = Unknown desc = error getting the volume for the mount c:\var\lib\kubelet\plugins\kubernetes.io\csi\ebs.csi.aws.com\1610843f84a51551af6fe5a45ef0fc4afcc8ac37f65a219815fccad076ef7dcc\globalmount, internal error error getting volume from mount. cmd: (Get-Item -Path Get-Item : Cannot find path 'C:\var\lib\kubelet\plugins\kubernetes.io\csi\ebs.csi.aws.com\1610843f84a51551af6fe5a45ef0f
	922efd496ae6e73900f42d7ccc7ef58c003\globalmount' because it does not exist.
	At line:1 char:2
	+ (Get-Item -Path c:\var\lib\kubelet\plugins\kubernetes.io\csi\ebs.csi. ...
	+  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
	    + CategoryInfo          : ObjectNotFound: (C:\var\lib\kube...003\globalmount:String) [Get-Item], ItemNotFoundExcep
	   tion
	    + FullyQualifiedErrorId : PathNotFound,Microsoft.PowerShell.Commands.GetItemCommand).Target, output: At line:2 char:76
	+ ... 496ae6e73900f42d7ccc7ef58c003\globalmount' because it does not exist.

I0303 01:42:25.179841     652 node.go:172] "NodeStageVolume: volume operation finished" volumeID="vol-0ce949dffa97f251a"
I0303 01:42:25.180392     652 inflight.go:74] "Node Service: volume operation finished" key="vol-0ce949dffa97f251a"
E0303 01:42:25.180392     652 driver.go:120] "GRPC error" err=<
	rpc error: code = Internal desc = could not format "3" and mount it at "\\var\\lib\\kubelet\\plugins\\kubernetes.io\\csi\\ebs.csi.aws.com\\914755ec302b648ec6285e1fe8790121c95058c4e191a432214a2a3472aac79c\\globalmount": rpc error: code = Unknown desc = error mount volume to path. cmd: Get-Volume -UniqueId "\\?\Volume{5baf4ea8-203e-477a-845c-77a024150315}\" | Get-Partition | Add-PartitionAccessPath -AccessPath c:\var\lib\kubelet\plugins\kubernetes.io\csi\ebs.csi.aws.com\914755ec302b648ec6285e1fe8790121c95058c4e191a432214a2a3472aac79c\globalmount, output: Add-PartitionAccessPath : The requested access path is already in use.
	Activity ID: {cb64fe87-eb6f-42de-a3dc-d2505bb47395}
	At line:1 char:92
	+ ... Partition | Add-PartitionAccessPath -AccessPath c:\var\lib\kubelet\pl ...
	+                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
	    + CategoryInfo          : InvalidArgument: (StorageWMI:ROOT/Microsoft/.../MSFT_Partition) [Add-PartitionAccessPath
	   ], CimException
	    + FullyQualifiedErrorId : StorageWMI 42002,Add-PartitionAccessPath

	, error: exit status 1

What testing is done?

$ kubetest2 noop \         
  --run-id="e2e-kubernetes" \
  --test=ginkgo \
  -- \
  --test-package-version=v1.27.0-alpha.3 \
  --skip-regex="\[Disruptive\]|\[Serial\]|\[LinuxOnly\]|\[Feature:VolumeSnapshotDataSource\]|(xfs)|(ext4)|(block volmode)|csinodes" \
  --focus-regex="External.Storage" \
  --parallel=15 \
  --test-args="-storage.testdriver=/home/torredil/go/src/github.com/torredil/aws-ebs-csi-driver/tests/e2e-kubernetes/manifests.yaml -node-os-distro=windows"

[ConnorJC3]

/lgtm

👍

[k8s-ci-robot]

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