Use planner.leveling_active for all leveling systems

Marlin/src/core/utility.cpp

Marlin/src/feature/bedlevel/bedlevel.cpp

Marlin/src/feature/bedlevel/bedlevel.h

Marlin/src/feature/bedlevel/mbl/mesh_bed_leveling.cpp

Marlin/src/feature/bedlevel/mbl/mesh_bed_leveling.h

Marlin/src/feature/bedlevel/ubl/ubl.cpp

Marlin/src/feature/bedlevel/ubl/ubl_G29.cpp

Marlin/src/feature/bedlevel/ubl/ubl_motion.cpp

Marlin/src/gcode/bedlevel/M420.cpp

Marlin/src/gcode/bedlevel/abl/G29.cpp

Marlin/src/gcode/bedlevel/mbl/G29.cpp

Marlin/src/gcode/calibrate/G28.cpp

Marlin/src/gcode/calibrate/M48.cpp

Marlin/src/lcd/ultralcd.cpp

Marlin/src/lcd/ultralcd_impl_HD44780.h

Marlin/src/module/configuration_store.cpp

Marlin/src/module/motion.cpp

Marlin/src/module/planner.cpp

Marlin/src/module/planner.h

Marlin/src/module/probe.cpp