Disable authorized IP ranges command fails(Cloud Shell PowerShell): az aks update --api-server-authorized-ip-ranges ""

Command from docs:
`az aks update --api-server-authorized-ip-ranges ""`

In Cloud Shell PowerShell fails with:
`argument --api-server-authorized-ip-ranges: expected one argument`

Same exact command works in Cloud Shell bash.

Not sure if this is a docs issue, where the command should look different in PS, or whether it's a bug in the az client when running from PowerShell (possibly a Windows vs Linux issue).

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#### Document Details

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* ID: d75c3a8d-1187-bea1-a7d4-7ebba71c1790
* Version Independent ID: 75b0c352-762e-16ae-5cc6-d807ffc1dc3f
* Content: [az aks](https://docs.microsoft.com/en-us/cli/azure/aks?view=azure-cli-latest)
* Content Source: [latest/docs-ref-autogen/aks.yml](https://github.com/MicrosoftDocs/azure-docs-cli/blob/master/latest/docs-ref-autogen/aks.yml)
* Service: **container-service**
* GitHub Login: @rloutlaw
* Microsoft Alias: **routlaw**