### 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
* Gets the recursive hash of a Variant.
 *
 * @param p_self A pointer to the Variant.
 * @param p_recursion_count The number of recursive loops so far.
 *
 * @return The hash value.
 *
 * @see Variant::recursive_hash()
 */
typedef GDExtensionInt (*GDExtensionInterfaceVariantRecursiveHash)(GDExtensionConstVariantPtr p_self, GDExtensionInt p_recursion_count);
/**
 * @name variant_hash_compare
 * @since 4.1
 *
 * Compares two Variants by their hash.
 *
 * @param p_self A pointer to the Variant.
 * @param p_other A pointer to the other Variant to compare it to.
 *
 * @return The hash value.
 *
 * @see Variant::hash_compare()
 */
typedef GDExtensionBool (*GDExtensionInterfaceVariantHashCompare)(GDExtensionConstVariantPtr p_self, GDExtensionConstVariantPtr p_other);
/**
 * @name variant_booleanize
 * @since 4.1
 *
 * Converts a Variant to a boolean.
 *