Add POWER_OFF_DELAY option (#19987)

Co-authored-by: Scott Lahteine <thinkyhead@users.noreply.github.com>

Marlin/src/feature/power.cpp

@@ -126,4 +126,12 @@ void Power::power_off() {
   }
 }
 
+void Power::power_off_soon() {
+  #if POWER_OFF_DELAY
+    lastPowerOn = millis() - SEC_TO_MS(POWER_TIMEOUT) + SEC_TO_MS(POWER_OFF_DELAY);
+  #else
+    power_off();
+  #endif
+}
+
 #endif // AUTO_POWER_CONTROL