Remove page on error so it can be retried.

Author: grokys

src/GitHub.App/Collections/VirtualizingList.cs

@@ -206,6 +206,7 @@ async void LoadPage(int number)
             catch (Exception ex)
             {
                 log.Error(ex, "Error loading virtualizing list page {Number}", number);
+                pages.Remove(number);
             }
         }