Fix role-based fan speeds being lost on layer change (#13390)

src/libslic3r/GCode.hpp

@@ -559,6 +559,7 @@ private:
     std::string _encode_label_ids_to_base64(std::vector<size_t> ids);
     // ORCA: Add support for role based fan speed control
     std::array<bool, ExtrusionRole::erCount> m_is_role_based_fan_on;
+    std::array<int, ExtrusionRole::erCount>  m_role_based_fan_marker_layer;
     // Markers for the Pressure Equalizer to recognize the extrusion type.
     // The Pressure Equalizer removes the markers from the final G-code.
     bool                                m_enable_extrusion_role_markers;