### 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
*
 * @return A const pointer to the requested 64-bit integer.
 */
typedef const int64_t *(*GDExtensionInterfacePackedInt64ArrayOperatorIndexConst)(GDExtensionConstTypePtr p_self, GDExtensionInt p_index);
/**
 * @name packed_string_array_operator_index
 * @since 4.1
 *
 * Gets a pointer to a string in a PackedStringArray.
 *
 * @param p_self A pointer to a PackedStringArray object.
 * @param p_index The index of the String to get.
 *
 * @return A pointer to the requested String.
 */
typedef GDExtensionStringPtr (*GDExtensionInterfacePackedStringArrayOperatorIndex)(GDExtensionTypePtr p_self, GDExtensionInt p_index);
/**
 * @name packed_string_array_operator_index_const
 * @since 4.1
 *
 * Gets a const pointer to a string in a PackedStringArray.
 *
 * @param p_self A const pointer to a PackedStringArray object.
 * @param p_index The index of the String to get.
 *
 * @return A const pointer to the requested String.
 */
typedef GDExtensionStringPtr (*GDExtensionInterfacePackedStringArrayOperatorIndexConst)(GDExtensionConstTypePtr p_self, GDExtensionInt p_index);
/**
 * @name packed_vector2_array_operator_index