Fix issue that skip object won't trigger filament change when print-b…

…y-object is used (#5576)

* Fix issue that skip object won't trigger filament change when print-by-object is used

src/libslic3r/GCode.cpp

@@ -2577,7 +2577,7 @@ void GCode::_do_export(Print& print, GCodeOutputStream &file, ThumbnailsGenerato
                     if (m_writer.need_toolchange(initial_extruder_id)) {
                         const PrintObjectConfig& object_config = object.config();
                         coordf_t initial_layer_print_height = print.config().initial_layer_print_height.value;
-                        file.write(this->set_extruder(initial_extruder_id, initial_layer_print_height));
+                        file.write(this->set_extruder(initial_extruder_id, initial_layer_print_height, true));
                         prime_extruder = true;
                     }
                     else {