### 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
r_godot_version->major = VERSION_MAJOR;
	r_godot_version->minor = VERSION_MINOR;
	r_godot_version->patch = VERSION_PATCH;
	r_godot_version->string = VERSION_FULL_NAME;
}
static void *gdextension_mem_alloc(size_t p_size) {
	return memalloc(p_size);
}
static void *gdextension_mem_realloc(void *p_mem, size_t p_size) {
	return memrealloc(p_mem, p_size);
}
static void gdextension_mem_free(void *p_mem) {
	memfree(p_mem);
}
static void gdextension_print_error(const char *p_description, const char *p_function, const char *p_file, int32_t p_line, GDExtensionBool p_editor_notify) {
	_err_print_error(p_function, p_file, p_line, p_description, p_editor_notify, ERR_HANDLER_ERROR);
}
static void gdextension_print_error_with_message(const char *p_description, const char *p_message, const char *p_function, const char *p_file, int32_t p_line, GDExtensionBool p_editor_notify) {
	_err_print_error(p_function, p_file, p_line, p_description, p_message, p_editor_notify, ERR_HANDLER_ERROR);
}
static void gdextension_print_warning(const char *p_description, const char *p_function, const char *p_file, int32_t p_line, GDExtensionBool p_editor_notify) {
	_err_print_error(p_function, p_file, p_line, p_description, p_editor_notify, ERR_HANDLER_WARNING);
}
static void gdextension_print_warning_with_message(const char *p_description, const char *p_message, const char *p_function, const char *p_file, int32_t p_line, GDExtensionBool p_editor_notify) {
	_err_print_error(p_function, p_file, p_line, p_description, p_message, p_editor_notify, ERR_HANDLER_WARNING);
}
static void gdextension_print_script_error(const char *p_description, const char *p_function, const char *p_file, int32_t p_line, GDExtensionBool p_editor_notify) {
	_err_print_error(p_function, p_file, p_line, p_description, p_editor_notify, ERR_HANDLER_SCRIPT);
}
static void gdextension_print_script_error_with_message(const char *p_description, const char *p_message, const char *p_function, const char *p_file, int32_t p_line, GDExtensionBool p_editor_notify) {