Enums defined with enum classes in-engine are not using enum classes in godot-cpp

### Godot version

Godot master

### godot-cpp version

Master of godot-cpp 6facde3c29abe4d8b0ff365c252c9aeb16fc5f66

### System information

macOS 14.6.1 arm64

### Issue description

Enums such as `Key`, `MouseButton`, `MouseButtonMask`, and more using `enum class` in-engine are not using `enum class` in godot-cpp, they are just using regular `enum`. Using `enum class` improves type safety, but I am not sure if Godot provides a mechanism for godot-cpp to know which enums are using `enum class`.

This issue is not super important because there is an easy workaround. In my project, I am using these defines that only get used when compiling as a module, and writing `KEY_` in my code, which auto-replace when compiled as a module.

```cpp
#if GODOT_MODULE
#define KEY_A Key::A
#define KEY_D Key::D
#define KEY_E Key::E
#define KEY_F Key::F
#define KEY_Q Key::Q
#define KEY_R Key::R
#define KEY_S Key::S
#define KEY_T Key::T
#define KEY_W Key::W
#define KEY_SHIFT Key::SHIFT

#define MOUSE_BUTTON_LEFT MouseButton::RIGHT
#define MOUSE_BUTTON_MASK_MIDDLE MouseButtonMask::MIDDLE
#define MOUSE_BUTTON_MASK_RIGHT MouseButtonMask::RIGHT
#define MOUSE_BUTTON_RIGHT MouseButton::RIGHT
#define MOUSE_BUTTON_WHEEL_UP MouseButton::WHEEL_UP
#define MOUSE_BUTTON_WHEEL_DOWN MouseButton::WHEEL_DOWN
#endif
```

### Steps to reproduce

Try using one of the values in the `Key` enum in-engine vs in godot-cpp.

### Minimal reproduction project

Trivial to reproduce with one line of code in a new godot-cpp GDExtension project.