fix azure disk list corruption issue

[andyzhangx]

What type of PR is this?
/kind bug

What this PR does / why we need it:
This PR fixed azure disk list corruption issue:
In Azure disk attach/detach function, it uses slice(disks) to store the disk list:

kubernetes/staging/src/k8s.io/legacy-cloud-providers/azure/azure_controller_standard.go

Line 44 in f01c140

disks := *vm.StorageProfile.DataDisks

And after disks changed, the original vm.StorageProfile.DataDisks would also be changed, so original azure data disk list is corrupted after attach/detach disk

example code as below:

func main() {
    var disks *[]string 
    disks = &[]string{"disk1", "disk2", "disk3", "disk4"}
    copy := *disks

    //detach a disk
    copy = append(copy[:1], copy[2:]...)

    
    fmt.Println("disks = ", *disks)
    fmt.Println("copy = ", copy)
}


# ./test
disks =  [disk1 disk3 disk4 disk4]
copy =  [disk1 disk3 disk4]

Which issue(s) this PR fixes:

Fixes #77186

Special notes for your reviewer:

release-note:

fix azure disk list corruption issue

/kind bug
/assign @feiskyer @khenidak
/priority important-soon
/sig azure

/test pull-kubernetes-e2e-aks-engine-azure

[justaugustus]

/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: andyzhangx, justaugustus

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Needs approval from an approver in each of these files:

• staging/src/k8s.io/legacy-cloud-providers/azure/OWNERS [andyzhangx]

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[andyzhangx]

/hold
hold a day for review

[feiskyer]

To avoid such issues again, @andyzhangx could you add a unit test for this?

[andyzhangx]

To avoid such issues again, @andyzhangx could you add a unit test for this?

I don't think it could be covered in unit test.

[andyzhangx]

@feiskyer any concern about this PR? I would like to cherry pick to older release ASAP.

[feiskyer]

lgtm

[andyzhangx]

/hold cancel