[ReleasePR monitor] [Hub Generated] Review request for Microsoft.Insights to add version preview/2021-09-01-preview (#2243)

Create to sync Azure/azure-rest-api-specs#17599
[ReCreate this PR](https://github.com/azure-resource-manager-schemas/compare/main...AzureSDKAutomation:sdkAuto/monitor?expand=1)

Author: msftbot[bot]