### 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
* @name variant_construct
 * @since 4.1
 *
 * Constructs a Variant of the given type, using the first constructor that matches the given arguments.
 *
 * @param p_type The Variant type.
 * @param p_base A pointer to a Variant to store the constructed value.
 * @param p_args A pointer to a C array of Variant pointers representing the arguments for the constructor.
 * @param p_argument_count The number of arguments to pass to the constructor.
 * @param r_error A pointer the structure which will be updated with error information.
 */
typedef void (*GDExtensionInterfaceVariantConstruct)(GDExtensionVariantType p_type, GDExtensionUninitializedVariantPtr r_base, const GDExtensionConstVariantPtr *p_args, int32_t p_argument_count, GDExtensionCallError *r_error);
/**
 * @name variant_get_ptr_setter
 * @since 4.1
 *
 * Gets a pointer to a function that can call a member's setter on the given Variant type.
 *
 * @param p_type The Variant type.
 * @param p_member A pointer to a StringName with the member name.
 *
 * @return A pointer to a function that can call a member's setter on the given Variant type.
 */
typedef GDExtensionPtrSetter (*GDExtensionInterfaceVariantGetPtrSetter)(GDExtensionVariantType p_type, GDExtensionConstStringNamePtr p_member);
/**
 * @name variant_get_ptr_getter
 * @since 4.1
 *
 * Gets a pointer to a function that can call a member's getter on the given Variant type.
 *