[gpio] Use a user provided default constructor for GPIOBinarySensor (#19143)

esphome/components/gpio/binary_sensor/gpio_binary_sensor.h

@@ -47,6 +47,9 @@ class GPIOBinarySensorStore {
 
 class GPIOBinarySensor final : public binary_sensor::BinarySensor, public Component {
  public:
+  // User provided, not "= default": `new(p) GPIOBinarySensor()` would zero-fill .bss that is already zero.
+  GPIOBinarySensor() {}
+
   // No destructor needed: ESPHome components are created at boot and live forever.
   // Interrupts are only detached on reboot when memory is cleared anyway.
 
@@ -70,7 +73,7 @@ class GPIOBinarySensor final : public binary_sensor::BinarySensor, public Compon
   void loop() override;
 
  protected:
-  GPIOPin *pin_;
+  GPIOPin *pin_{nullptr};
   GPIOBinarySensorStore store_;
 };