[NuGet] Fix license expression links in License Acceptance dialog

Using the non-native XWT toolkit to display the dialog allows the
hyperlinks to be clicked. It also fixes the scrollbars showing a
whitebackground, even when not used.

Looked at adding the resize logic back, which would reduce the
height of the dialog based on the contents. However using the XWT
toolkit which is non-native (GTK#) the dialog is displayed first
and then resized so you can see it shrink. Instead the dialog does
not resize to fit its contents which leaves some empty space.

Author: mrward

main/src/addins/MonoDevelop.PackageManagement/MonoDevelop.PackageManagement/LicenseAcceptanceService.cs

@@ -47,11 +47,13 @@ Task<bool> ShowLicenseAcceptanceDialog (IEnumerable<NuGetPackageLicense> license
 		{
 			var res = new TaskCompletionSource<bool> ();
 			IdeApp.RunWhenIdle (() => {
-				Xwt.Toolkit.NativeEngine.Invoke (delegate {
+				// Disable use of native toolkit since hyperlinks cannot be clicked with the Xamarin.Mac LabelBackend
+				// Also scrollbars are always visible even when they are not needed.
+				//Xwt.Toolkit.NativeEngine.Invoke (delegate {
 					using (LicenseAcceptanceDialog dialog = CreateLicenseAcceptanceDialog (licenses)) {
 						res.SetResult (dialog.Run (Xwt.MessageDialog.RootWindow));
 					}
-				});
+				//});
 			});
 			return res.Task;
 		}