Add browser auth for headless runs

Runtime/IntuneManagement.Runtime.psm1

@@ -17,6 +17,9 @@ function Initialize-IntuneManagementRuntime
         [string]$AppId,
         [string]$Secret,
         [string]$Certificate,
+        [ValidateSet("AppOnly","Browser")]
+        [string]$AuthMode = "AppOnly",
+        [string]$RedirectUri,
         [string]$GraphEnvironment,
         [string]$GCCType
     )
@@ -30,6 +33,8 @@ function Initialize-IntuneManagementRuntime
     $global:AzureAppId = $AppId
     $global:ClientSecret = $Secret
     $global:ClientCert = $Certificate
+    $global:HeadlessAuthMode = $AuthMode
+    $global:MSALRedirectUri = $RedirectUri
     $global:UseGraphEnvironment = $GraphEnvironment
     $global:UseGCCType = $GCCType
     $global:UseJSonSettings = ($JSonSettings -eq $true)
@@ -68,6 +73,10 @@ function Initialize-IntuneManagementRuntime
     {
         Write-Host "Using Azure App Certificate"
     }
+    elseif($global:HeadlessAuthMode -eq "Browser")
+    {
+        Write-Host "Using browser authentication"
+    }
     else
     {
         Write-Warning "Azure App Secret or Certificate is missing. Use -Secret <Secret> or -Certificate <Certificate>."