[pca9554] Use a user provided default constructor for PCA9554GPIOPin (#19208)

esphome/components/pca9554/pca9554.h

@@ -55,6 +55,9 @@ class PCA9554Component final : public Component,
 /// Helper class to expose a PCA9554 pin as an internal input GPIO pin.
 class PCA9554GPIOPin final : public GPIOPin {
  public:
+  // User provided, not "= default": `new(p) PCA9554GPIOPin()` would zero-fill .bss that is already zero.
+  PCA9554GPIOPin() {}
+
   void setup() override;
   void pin_mode(gpio::Flags flags) override;
   bool digital_read() override;
@@ -69,10 +72,10 @@ class PCA9554GPIOPin final : public GPIOPin {
   gpio::Flags get_flags() const override { return this->flags_; }
 
  protected:
-  PCA9554Component *parent_;
-  uint8_t pin_;
-  bool inverted_;
-  gpio::Flags flags_;
+  PCA9554Component *parent_{nullptr};
+  uint8_t pin_{0};
+  bool inverted_{false};
+  gpio::Flags flags_{};
 };
 
 }  // namespace esphome::pca9554