Fix: Fixed issue where third party licenses were not displayed (#14150)

src/Files.App/Views/Settings/AboutPage.xaml.cs

@@ -16,7 +16,7 @@ public AboutPage()
 
 		private async void ThirdPartyLicenses_Click(object sender, bool e)
 		{
-			if (e && ViewModel.ThirdPartyNotices is null)
+			if (e && string.IsNullOrEmpty(ViewModel.ThirdPartyNotices))
 				await ViewModel.LoadThirdPartyNoticesAsync();
 		}