Clear the last_mod_toggled stack.

Otherwise if a provides throws a InconsistentKraken the contents would leak.

GUI/Main.cs

@@ -621,7 +621,7 @@ await mainModList.ComputeChangeSetFromModList(registry, user_change_set, module_
                 conflicts = Conflicts;
                 full_change_set = ChangeSet;
             }
-
+            last_mod_to_have_install_toggled.Clear();
             Conflicts = conflicts;
             ChangeSet = full_change_set;
         }