Remove atscope param as part of breaking change

[darshanhs90]

Linked to #5676

Description

Checklist

• I have read the Submitting Changes section of CONTRIBUTING.md
• The title of the PR is clear and informative
• The appropriate change log has been updated
• The PR does not introduce breaking changes
• If applicable, the changes made in the PR have proper test coverage
• For public API changes to cmdlets:
  • the changes have gone through a cmdlet design review
  • the cmdlet markdown files were generated using the platyPS module

[darshanhs90]

@maddieclayton as part of the breaking change release,should i do any extra step apart from removing the obsolete tags?
The build is failing because of the breaking change issue

[maddieclayton]

@darshanhs90 You will need to add an entry to the breakingchanges.csv file (instructions here)

[maddieclayton]

on demand job here: https://azuresdkci.westus2.cloudapp.azure.com/view/PowerShell/job/powershell-demand/744/