### 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
*
 * You can then call it like a normal function:
 *
 *   GDExtensionGodotVersion godot_version;
 *   get_godot_version(&godot_version);
 *   printf("Godot v%d.%d.%d\n", godot_version.major, godot_version.minor, godot_version.patch);
 *
 * All of these interface functions are described below, together with the name that's used to load it,
 * and the function pointer typedef that shows its signature.
 */
typedef GDExtensionBool (*GDExtensionInitializationFunction)(GDExtensionInterfaceGetProcAddress p_get_proc_address, GDExtensionClassLibraryPtr p_library, GDExtensionInitialization *r_initialization);
typedef struct {
	uint32_t major;
	uint32_t minor;
	uint32_t patch;
	const char *string;
} GDExtensionGodotVersion;
/**
 * @name get_godot_version
 * @since 4.1
 *
 * Gets the Godot version that the GDExtension was loaded into.
 *
 * @param r_godot_version A pointer to the structure to write the version information into.
 */
typedef void (*GDExtensionInterfaceGetGodotVersion)(GDExtensionGodotVersion *r_godot_version);
/**
 * @name mem_alloc
 * @since 4.1
 *