### 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
*
 * @param p_o A pointer to the Object.
 * @param p_library A token the library received by the GDExtension's entry point function.
 * @param p_binding A pointer to the instance binding.
 * @param p_callbacks A pointer to a GDExtensionInstanceBindingCallbacks struct.
 */
typedef void (*GDExtensionInterfaceObjectSetInstanceBinding)(GDExtensionObjectPtr p_o, void *p_token, void *p_binding, const GDExtensionInstanceBindingCallbacks *p_callbacks);
/**
 * @name object_set_instance
 * @since 4.1
 *
 * Sets an extension class instance on a Object.
 *
 * @param p_o A pointer to the Object.
 * @param p_classname A pointer to a StringName with the registered extension class's name.
 * @param p_instance A pointer to the extension class instance.
 */
typedef void (*GDExtensionInterfaceObjectSetInstance)(GDExtensionObjectPtr p_o, GDExtensionConstStringNamePtr p_classname, GDExtensionClassInstancePtr p_instance); 
/**
 * @name object_get_class_name
 * @since 4.1
 *
 * Gets the class name of an Object.
 *
 * @param p_object A pointer to the Object.
 * @param p_library A pointer the library received by the GDExtension's entry point function.
 * @param r_class_name A pointer to a String to receive the class name.
 *
 * @return true if successful in getting the class name; otherwise false.
 */