[Bug fix] Update code for Get-AzSecurityContact error - introduced due to PS module bug

[dutt0]

Overview/Summary

The command Get-AzSecurityContact gives a 'unable to deserialize the response' error. This error is only noticeable for Az.Security version 1.5.1 with runtime PS v5.1. This pull request has updated code to have a workaround for this Az.Security module bug.

This PR fixes/adds/changes/removes

This pull request has the fix using management security API

Additional context

A combination of Az.security version v1.3.0/ v1.4.0 and PS v5.1 works as expected with no error in runbook.
Az.security version v1.5.0 and PS v5.1 combination was not tested.

Testing Evidence

As part of this Pull Request I have

• Checked for duplicate Pull Requests
• Associated it with relevant GitHub Issues
• Ensured my code/branch is up-to-date with the latest changes in the main branch
• Performed testing and provided evidence.
• Updated relevant and associated documentation.
• Ensure PowerShell module versions have been updated (manually or with the ./tools/Update-ModuleVersions.ps1 script)