Support creating resources with user auth

eng/common/TestResources/New-TestResources.ps1

@@ -92,6 +92,9 @@ param (
     [Parameter()]
     [switch] $SuppressVsoCommands = ($null -eq $env:SYSTEM_TEAMPROJECTID),
 
+    [Parameter()]
+    [switch] $UseUserCredentials,
+
     # Captures any arguments not declared here (no parameter errors)
     # This enables backwards compatibility with old script versions in
     # hotfix branches if and when the dynamic subscription configuration
@@ -611,8 +614,14 @@ try {
         }
     }
 
+
+    if ($UseUserCredentials) {
+        $TestApplicationOid = (Get-AzADUser -UserPrincipalName (Get-AzContext).Account).Id
+        $TestApplicationId = $testApplicationOid
+        Log "User-based app id '$TestApplicationId' will be used."
+    }
     # If no test application ID was specified during an interactive session, create a new service principal.
-    if (!$CI -and !$TestApplicationId) {
+    elseif (!$CI -and !$TestApplicationId) {
         # Cache the created service principal in this session for frequent reuse.
         $servicePrincipal = if ($AzureTestPrincipal -and (Get-AzADServicePrincipal -ApplicationId $AzureTestPrincipal.AppId) -and $AzureTestSubscription -eq $SubscriptionId) {
             Log "TestApplicationId was not specified; loading cached service principal '$($AzureTestPrincipal.AppId)'"
@@ -1001,6 +1010,14 @@ The environment file will be named for the test resources template that it was
 generated for. For ARM templates, it will be test-resources.json.env. For
 Bicep templates, test-resources.bicep.env.
 
+.PARAMETER UseUserCredentials
+Create the resource group and deploy the template using the signed in user's credentials.
+No service principal will be created or used.
+
+The environment file will be named for the test resources template that it was
+generated for. For ARM templates, it will be test-resources.json.env. For
+Bicep templates, test-resources.bicep.env.
+
 .PARAMETER SuppressVsoCommands
 By default, the -CI parameter will print out secrets to logs with Azure Pipelines log
 commands that cause them to be redacted. For CI environments that don't support this (like