Fix backlight sync on suspend_power_down for split keyboards (#21079)

quantum/quantum.c

@@ -468,7 +468,7 @@ void suspend_power_down_quantum(void) {
 #ifndef NO_SUSPEND_POWER_DOWN
 // Turn off backlight
 #    ifdef BACKLIGHT_ENABLE
-    backlight_set(0);
+    backlight_level_noeeprom(0);
 #    endif
 
 #    ifdef LED_MATRIX_ENABLE

quantum/split_common/transactions.c

@@ -412,7 +412,7 @@ static void backlight_handlers_slave(matrix_row_t master_matrix[], matrix_row_t
     uint8_t backlight_level = split_shmem->backlight_level;
     split_shared_memory_unlock();
 
-    backlight_set(backlight_level);
+    backlight_level_noeeprom(backlight_level);
 }
 
 #    define TRANSACTIONS_BACKLIGHT_MASTER() TRANSACTION_HANDLER_MASTER(backlight)