### 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_object A pointer to the Object.
 *
 * @return The instance ID.
 */
typedef GDObjectInstanceID (*GDExtensionInterfaceObjectGetInstanceId)(GDExtensionConstObjectPtr p_object);
/**
 * @name ref_get_object
 * @since 4.1
 *
 * Gets the Object from a reference.
 *
 * @param p_ref A pointer to the reference.
 *
 * @return A pointer to the Object from the reference or NULL.
 */
typedef GDExtensionObjectPtr (*GDExtensionInterfaceRefGetObject)(GDExtensionConstRefPtr p_ref);
/**
 * @name ref_set_object
 * @since 4.1
 *
 * Sets the Object referred to by a reference.
 *
 * @param p_ref A pointer to the reference.
 * @param p_object A pointer to the Object to refer to.
 */
typedef void (*GDExtensionInterfaceRefSetObject)(GDExtensionRefPtr p_ref, GDExtensionObjectPtr p_object);
/**
 * @name script_instance_create
 * @since 4.1
 * @deprecated in Godot 4.2. Use `script_instance_create2` instead.