### Godot version

4.2 247c354

### System information

Windows 10.0.19045 - Vulkan (Forward+) - dedicated NVIDIA GeForce GTX 1060 (NVIDIA; 30.0.15.1403) - Intel(R) Core(TM) i7-7700HQ CPU @ 2.80GHz (8 Threads)

### Issue description

#75778 exposed `_validate_property()` to scripting. It's implemented in GDScript and C#, but not GDExtension (depends on #78634).
https://github.com/godotengine/godot/blob/247c3548d810136ffe9c1694cd76db3236efaa90/core/object/script_language_extension.h#L685-L687

Relevant discussion: https://github.com/godotengine/godot/pull/75778#discussion_r1307294940

### Steps to reproduce

1. Add GDExtension script
2. Use `_validate_property()`

### Minimal reproduction project

N/A
typedef GDExtensionBool (*GDExtensionInterfaceObjectGetClassName)(GDExtensionConstObjectPtr p_object, GDExtensionClassLibraryPtr p_library, GDExtensionUninitializedStringNamePtr r_class_name);
/**
 * @name object_cast_to
 * @since 4.1
 *
 * Casts an Object to a different type.
 *
 * @param p_object A pointer to the Object.
 * @param p_class_tag A pointer uniquely identifying a built-in class in the ClassDB.
 *
 * @return Returns a pointer to the Object, or NULL if it can't be cast to the requested type.
 */
typedef GDExtensionObjectPtr (*GDExtensionInterfaceObjectCastTo)(GDExtensionConstObjectPtr p_object, void *p_class_tag);
/**
 * @name object_get_instance_from_id
 * @since 4.1
 *
 * Gets an Object by its instance ID.
 *
 * @param p_instance_id The instance ID.
 *
 * @return A pointer to the Object.
 */
typedef GDExtensionObjectPtr (*GDExtensionInterfaceObjectGetInstanceFromId)(GDObjectInstanceID p_instance_id);
/**
 * @name object_get_instance_id
 * @since 4.1
 *
 * Gets the instance ID from an Object.
 *