FTM: add Z_LATE_ENABLE feature

Marlin/src/inc/SanityCheck.h

@@ -4758,8 +4758,6 @@ static_assert(_PLUS_TEST(3), "DEFAULT_MAX_ACCELERATION values must be positive."
       #error "DIFFERENTIAL_EXTRUDER is not yet available in FT_MOTION. Disable NO_STANDARD_MOTION if you require it."
     #elif ENABLED(LASER_FEATURE)
       #error "LASER_FEATURE is not yet available in FT_MOTION. Disable NO_STANDARD_MOTION if you require it."
-    #elif ENABLED(Z_LATE_ENABLE)
-      #error "Z_LATE_ENABLE is not yet available in FT_MOTION. Disable NO_STANDARD_MOTION if you require it."
     #endif
   #endif
   #if HAS_FTM_SHAPING && NONE(FTM_SHAPER_ZV, FTM_SHAPER_ZVD, FTM_SHAPER_ZVDD, FTM_SHAPER_ZVDDD, FTM_SHAPER_EI, FTM_SHAPER_2HEI, FTM_SHAPER_3HEI, FTM_SHAPER_MZV)

Marlin/src/module/ft_motion.cpp

@@ -436,6 +436,10 @@ bool FTMotion::plan_next_block() {
     // triggered endstop, which marks the block for discard on the next ISR.
     endstops.update();
 
+    #if ENABLED(Z_LATE_ENABLE)
+      if (moving_axis_flags.rz) stepper.enable_axis(Z_AXIS);
+    #endif
+
     return true;
   } // infinite loop
 }