[ReleasePR iothub] Revert "[Hub Generated] Review request for Microsoft.Devices to add version preview/2021-09-01-preview" (#1864)

Create to sync Azure/azure-rest-api-specs#15797
[ReCreate this PR](https://github.com/azure-resource-manager-schemas/compare/main...AzureSDKAutomation:sdkAuto/iothub?expand=1)

Author: msftbot[bot]