Use 'H' value for UBL G29 z-clearance (#21114)

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

       const xyz_pos_t ppos = {
         mesh_index_to_xpos(lpos.x),
         mesh_index_to_ypos(lpos.y),
-        Z_CLEARANCE_BETWEEN_PROBES
+        z_clearance
       };
 
       if (!position_is_reachable(ppos)) break; // SHOULD NOT OCCUR (find_closest_mesh_point only returns reachable points)
 
       if (do_ubl_mesh_map) display_map(g29_map_type);  // show user where we're probing
 
-      serialprintPGM(parser.seen('B') ? GET_TEXT(MSG_UBL_BC_INSERT) : GET_TEXT(MSG_UBL_BC_INSERT2));
+      if (parser.seen('B')) {
+        serialprintPGM(GET_TEXT(MSG_UBL_BC_INSERT));
+        LCD_MESSAGEPGM(MSG_UBL_BC_INSERT);
+      }
+      else {
+        serialprintPGM(GET_TEXT(MSG_UBL_BC_INSERT2));
+        LCD_MESSAGEPGM(MSG_UBL_BC_INSERT2);
+      }
 
       const float z_step = 0.01f;                         // existing behavior: 0.01mm per click, occasionally step
       //const float z_step = planner.steps_to_mm[Z_AXIS]; // approx one step each click