Disable realtime monitoring in the PR-validation pipeline (#77303)

Author: akhera99

azure-pipelines-pr-validation.yml

@@ -143,6 +143,9 @@ extends:
             ArtifactName: AssetManifests
 
         steps:
+        - pwsh: Set-MpPreference -DisableRealtimeMonitoring $true
+          displayName: Disable Real-time Monitoring
+          
         - powershell: Write-Host "##vso[task.setvariable variable=OriginalBuildNumber;isreadonly=true]$('$(Build.BuildNumber)')"
           displayName: Setting OriginalBuildNumber variable
           condition: succeeded()