Only enable wakeup via EXT_CHRG_DETECT if we shut down due to low power (#10263)

src/power.h

@@ -100,6 +100,7 @@ class Power : public concurrency::OSThread
     virtual int32_t runOnce() override;
     void setStatusHandler(meshtastic::PowerStatus *handler) { statusHandler = handler; }
     const uint16_t OCV[11] = {OCV_ARRAY};
+    bool isLowBattery() { return low_voltage_counter >= 10; };
 
 #ifdef ARCH_ESP32
     int beforeLightSleep(void *unused);