Allow passing in the Entra token (#4419)

Partially reverted #4415
where we still want to be able to pass in the token. This happens in the
scenario tests where we get it from Azure CLI manually.

src/Microsoft.DotNet.Darc/Darc/Options/CommandLineOptions.cs

@@ -28,19 +28,9 @@ public override Operation GetOperation(ServiceProvider sp)
 public abstract class CommandLineOptions : ICommandLineOptions
 {
     [Option('p', "password",
-        HelpText = "[DEPRECATED] Token used to authenticate to BAR. Please use Azure CLI or an interactive browser login flow.")]
+        HelpText = "Token used to authenticate to BAR. When omitted, Azure CLI or an interactive browser login flow are used.")]
     [RedactFromLogging]
-    public string BuildAssetRegistryToken
-    {
-        get => null;
-        set
-        {
-            if (!string.IsNullOrEmpty(value))
-            {
-                Console.WriteLine("The --password option is deprecated. Please use Azure CLI or an interactive browser login flow.");
-            }
-        }
-    }
+    public string BuildAssetRegistryToken { get; set; } = null;
 
     [Option("github-pat", HelpText = "Token used to authenticate GitHub.")]
     [RedactFromLogging]