Fix G28 leveling state, UBL compile (#20499)

Marlin/src/gcode/calibrate/G28.cpp

@@ -241,8 +241,8 @@ void GcodeSuite::G28() {
 
   // Disable the leveling matrix before homing
   #if HAS_LEVELING
-    const bool leveling_restore_state = ENABLED(ENABLE_LEVELING_AFTER_G28) || TERN0(RESTORE_LEVELING_AFTER_G28, planner.leveling_active);
-    TERN_(PROBE_MANUALLY, g29_in_progress = false);  // Cancel the active G29 session
+    IF_ENABLED(RESTORE_LEVELING_AFTER_G28, const bool leveling_restore_state = planner.leveling_active);
+    IF_ENABLED(PROBE_MANUALLY, g29_in_progress = false); // Cancel the active G29 session
     set_bed_leveling_enabled(false);
   #endif
 
@@ -435,7 +435,8 @@ void GcodeSuite::G28() {
     do_blocking_move_to_z(delta_clip_start_height);
   #endif
 
-  TERN_(RESTORE_LEVELING_AFTER_G28, set_bed_leveling_enabled(leveling_restore_state));
+  IF_ENABLED(RESTORE_LEVELING_AFTER_G28, set_bed_leveling_enabled(leveling_restore_state));
+  IF_ENABLED(ENABLE_LEVELING_AFTER_G28, set_bed_leveling_enabled(true));
 
   restore_feedrate_and_scaling();
 

Marlin/src/inc/Conditionals_LCD.h

@@ -886,6 +886,7 @@
 #if !HAS_LEVELING
   #undef PROBE_MANUALLY
   #undef RESTORE_LEVELING_AFTER_G28
+  #undef ENABLE_LEVELING_AFTER_G28
 #endif
 
 #ifdef GRID_MAX_POINTS_X

Marlin/src/inc/SanityCheck.h

@@ -1455,8 +1455,6 @@ static_assert(Y_MAX_LENGTH >= Y_BED_SIZE, "Movement bounds (Y_MIN_POS, Y_MAX_POS
     #error "AUTO_BED_LEVELING_UBL requires EEPROM_SETTINGS."
   #elif !WITHIN(GRID_MAX_POINTS_X, 3, 15) || !WITHIN(GRID_MAX_POINTS_Y, 3, 15)
     #error "GRID_MAX_POINTS_[XY] must be a whole number between 3 and 15."
-  #elif !defined(RESTORE_LEVELING_AFTER_G28) && !defined(ENABLE_LEVELING_AFTER_G28)
-    #error "AUTO_BED_LEVELING_UBL used to enable RESTORE_LEVELING_AFTER_G28. To keep this behavior enable RESTORE_LEVELING_AFTER_G28. Otherwise define it as 'false'."
   #endif
 
 #elif HAS_ABL_NOT_UBL