Tables: mark setting as dirty when forcing reordering.

Otherwise the manufactured case of reloading a session that previously had e.g. a slider to adjust freeze count, resetting to 1 on new session, would keep showing you reordering items until another thing triggers marking dirty.

imgui_tables.cpp

@@ -1692,6 +1692,7 @@ void ImGui::TableSetupScrollFreeze(int columns, int rows)
         {
             ImSwap(table->Columns[table->DisplayOrderToIndex[order_n]].DisplayOrder, table->Columns[table->DisplayOrderToIndex[column_n]].DisplayOrder);
             ImSwap(table->DisplayOrderToIndex[order_n], table->DisplayOrderToIndex[column_n]);
+            table->IsSettingsDirty = true;
         }
     }
 }