fix issue with codes with leading zero

Author: gluap

custom_components/duofern/config_flow.py

@@ -21,7 +21,7 @@ async def async_step_user(self, user_input: Mapping[str, Any]|None =None) -> Flo
                 errors["base"] = "not_hex"
             else:
                 try:
-                    if hex(int(user_input['code'], 16)).lower() != "0x" + user_input['code'].lower():
+                    if f"0x{int(user_input['code'],16):04x}" != "0x" + user_input['code'].lower():
                         errors["base"] = "not_hex"
                 except ValueError:
                     errors["base"] = "not_hex"