[ReleasePR monitor] Add 2021-05-01-preview swagger API support for Autoscale newly added fields and new controller path. (#1993)

Create to sync Azure/azure-rest-api-specs#16463
[ReCreate this PR](https://github.com/azure-resource-manager-schemas/compare/main...AzureSDKAutomation:sdkAuto/monitor?expand=1)

Author: msftbot[bot]