Use wait_for_bed with WAIT_FOR_BED_HEATER

Addressing #12517

Marlin/src/module/motion.cpp

     if (axis == Z_AXIS && distance < 0 && thermalManager.isHeatingBed()) {
       serialprintPGM(msg_wait_for_bed_heating);
       LCD_MESSAGEPGM(MSG_BED_HEATING);
-      while (thermalManager.isHeatingBed()) safe_delay(200);
+      thermalManager.wait_for_bed();
       ui.reset_status();
     }
   #endif

Marlin/src/module/probe.cpp

     if (thermalManager.isHeatingBed()) {
       serialprintPGM(msg_wait_for_bed_heating);
       LCD_MESSAGEPGM(MSG_BED_HEATING);
-      while (thermalManager.isHeatingBed()) safe_delay(200);
+      thermalManager.wait_for_bed();
       ui.reset_status();
     }
   #endif