Fix blocking delay in Photo G-code M240 (#15728)

Marlin/src/gcode/feature/camera/M240.cpp

   #if PIN_EXISTS(CHDK)
 
     OUT_WRITE(CHDK_PIN, HIGH);
-    chdk_timeout = millis() + PHOTO_SWITCH_MS;
+    chdk_timeout = millis() + parser.intval('D', PHOTO_SWITCH_MS);
 
   #elif HAS_PHOTOGRAPH
 
 
   #ifdef PHOTO_POSITION
     #if PHOTO_DELAY_MS > 0
-      safe_delay(parser.intval('P', PHOTO_DELAY_MS));
+      const millis_t timeout = millis() + parser.intval('P', PHOTO_DELAY_MS);
+      while (PENDING(millis(), timeout)) idle();
     #endif
     do_blocking_move_to(old_pos, fr_mm_s);
     #ifdef PHOTO_RETRACT_MM