🎨 Fix "'EEPROM' unused" warning (#22511)

Marlin/src/HAL/STM32/eeprom_flash.cpp

 
 bool PersistentStore::access_start() {
 
+  EEPROM.begin(); // Avoid STM32 EEPROM.h warning (do nothing)
+
   #if ENABLED(FLASH_EEPROM_LEVELING)
 
     if (current_slot == -1 || eeprom_data_written) {