Adding AuxiliaryMode property to New-AzNetworkInterface cmdlet

[pr-work]

Description

Adding property AuxiliaryMode to New-AzNetworkInterface cmdlet
Added tests as well

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:
  • 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
• For public API changes to cmdlets:
  • a cmdlet design review was approved for the changes in this repository (Microsoft internal only)
    • { Add AuxiliaryMode property to NetworkInterface · Issue #1181 · Azure/azure-powershell-cmdlet-review-pr (github.com)
      }
  • the markdown help files have been regenerated using the commands listed here

[wyunchi-ms]

/azp run azure-powershell - security-tools

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[isra-fel]

LGTM

[isra-fel]

/azp run azure-powershell - security-tools

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).