Correct command in Test-AzResourceGroupDeployment example in documentation

[GageAmes]

Description

Example 2 for Test-AzResourceGroupDeployment documentation was using the wrong command (New-AzResourceGroupDeployment instead of Test-AzResourceGroupDeployment)

Checklist

• I have read the Submitting Changes section of CONTRIBUTING.md
• The title of the PR is clear and informative
• The appropriate ChangeLog.md file(s) has been updated: (N/A)
  • For any service, the ChangeLog.md file can be found at src/{{SERVICE}}/{{SERVICE}}/ChangeLog.md
  • A snippet outlining the change(s) made in the PR should be written under the ## Upcoming Release header -- no new version header should be added
• The PR does not introduce breaking changes
• If applicable, the changes made in the PR have proper test coverage (N/A)
• For public API changes to cmdlets: (N/A)
  • a cmdlet design review was approved for the changes in this repository (Microsoft internal only) (N/A)
  • the markdown help files have been regenerated using the commands listed here (N/A)

[adxsdkps]

Can one of the admins verify this patch?