_validate_property() for GDExtension is not implemented

[KoBeWi]

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).

godot/core/object/script_language_extension.h

Lines 685 to 687 in 247c354

	virtual void validate_property(PropertyInfo &p_property) const override {
	// TODO
	}

Relevant discussion: #75778 (comment)

Steps to reproduce

1. Add GDExtension script
2. Use _validate_property()

Minimal reproduction project

N/A