### 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
* @param p_info A pointer to a GDExtensionPropertyInfo struct.
 * @param p_setter A pointer to a StringName with the name of the setter method.
 * @param p_getter A pointer to a StringName with the name of the getter method.
 * @param p_index The index to pass as the first argument to the getter and setter methods.
 */
typedef void (*GDExtensionInterfaceClassdbRegisterExtensionClassPropertyIndexed)(GDExtensionClassLibraryPtr p_library, GDExtensionConstStringNamePtr p_class_name, const GDExtensionPropertyInfo *p_info, GDExtensionConstStringNamePtr p_setter, GDExtensionConstStringNamePtr p_getter, GDExtensionInt p_index);
/**
 * @name classdb_register_extension_class_property_group
 * @since 4.1
 *
 * Registers a property group on an extension class in the ClassDB.
 *
 * @param p_library A pointer the library received by the GDExtension's entry point function.
 * @param p_class_name A pointer to a StringName with the class name.
 * @param p_group_name A pointer to a String with the group name.
 * @param p_prefix A pointer to a String with the prefix used by properties in this group.
 */
typedef void (*GDExtensionInterfaceClassdbRegisterExtensionClassPropertyGroup)(GDExtensionClassLibraryPtr p_library, GDExtensionConstStringNamePtr p_class_name, GDExtensionConstStringPtr p_group_name, GDExtensionConstStringPtr p_prefix);
/**
 * @name classdb_register_extension_class_property_subgroup
 * @since 4.1
 *
 * Registers a property subgroup on an extension class in the ClassDB.
 *
 * @param p_library A pointer the library received by the GDExtension's entry point function.
 * @param p_class_name A pointer to a StringName with the class name.
 * @param p_subgroup_name A pointer to a String with the subgroup name.
 * @param p_prefix A pointer to a String with the prefix used by properties in this subgroup.
 */
typedef void (*GDExtensionInterfaceClassdbRegisterExtensionClassPropertySubgroup)(GDExtensionClassLibraryPtr p_library, GDExtensionConstStringNamePtr p_class_name, GDExtensionConstStringPtr p_subgroup_name, GDExtensionConstStringPtr p_prefix);