♻️ Consolidate PSU_CONTROL (#22304)

Marlin/src/lcd/menu/menu_led.cpp

@@ -30,6 +30,10 @@
 
 #include "menu_item.h"
 
+#if ENABLED(PSU_CONTROL)
+  #include "../../feature/power.h"
+#endif
+
 #if ENABLED(LED_CONTROL_MENU)
   #include "../../feature/leds/leds.h"
 
@@ -125,12 +129,7 @@ void menu_led() {
   BACK_ITEM(MSG_MAIN);
 
   #if ENABLED(LED_CONTROL_MENU)
-    #if ENABLED(PSU_CONTROL)
-      extern bool powersupply_on;
-    #else
-      constexpr bool powersupply_on = true;
-    #endif
-    if (powersupply_on) {
+    if (TERN1(PSU_CONTROL, powerManager.psu_on)) {
       editable.state = leds.lights_on;
       EDIT_ITEM(bool, MSG_LEDS, &editable.state, leds.toggle);
     }