[deep_sleep] Fix wakeup_pin_mode rejecting lowercase on ESP32/BK72XX (#15384)

esphome/components/deep_sleep/__init__.py

@@ -266,8 +266,7 @@ CONFIG_SCHEMA = cv.All(
             cv.Optional(CONF_WAKEUP_PIN): validate_wakeup_pin,
             cv.Optional(CONF_WAKEUP_PIN_MODE): cv.All(
                 cv.only_on([PLATFORM_ESP32, PLATFORM_BK72XX]),
-                cv.enum(WAKEUP_PIN_MODES),
-                upper=True,
+                cv.enum(WAKEUP_PIN_MODES, upper=True),
             ),
             cv.Optional(CONF_ESP32_EXT1_WAKEUP): cv.All(
                 cv.only_on_esp32,