### 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 VariantTypeConstructor<Transform2D>::variant_from_type;
		case GDEXTENSION_VARIANT_TYPE_VECTOR4:
			return VariantTypeConstructor<Vector4>::variant_from_type;
		case GDEXTENSION_VARIANT_TYPE_VECTOR4I:
			return VariantTypeConstructor<Vector4i>::variant_from_type;
		case GDEXTENSION_VARIANT_TYPE_PLANE:
			return VariantTypeConstructor<Plane>::variant_from_type;
		case GDEXTENSION_VARIANT_TYPE_QUATERNION:
			return VariantTypeConstructor<Quaternion>::variant_from_type;
		case GDEXTENSION_VARIANT_TYPE_AABB:
			return VariantTypeConstructor<AABB>::variant_from_type;
		case GDEXTENSION_VARIANT_TYPE_BASIS:
			return VariantTypeConstructor<Basis>::variant_from_type;
		case GDEXTENSION_VARIANT_TYPE_TRANSFORM3D:
			return VariantTypeConstructor<Transform3D>::variant_from_type;
		case GDEXTENSION_VARIANT_TYPE_PROJECTION:
			return VariantTypeConstructor<Projection>::variant_from_type;
		case GDEXTENSION_VARIANT_TYPE_COLOR:
			return VariantTypeConstructor<Color>::variant_from_type;
		case GDEXTENSION_VARIANT_TYPE_STRING_NAME:
			return VariantTypeConstructor<StringName>::variant_from_type;
		case GDEXTENSION_VARIANT_TYPE_NODE_PATH:
			return VariantTypeConstructor<NodePath>::variant_from_type;
		case GDEXTENSION_VARIANT_TYPE_RID:
			return VariantTypeConstructor<RID>::variant_from_type;
		case GDEXTENSION_VARIANT_TYPE_OBJECT:
			return VariantTypeConstructor<Object *>::variant_from_type;
		case GDEXTENSION_VARIANT_TYPE_CALLABLE:
			return VariantTypeConstructor<Callable>::variant_from_type;
		case GDEXTENSION_VARIANT_TYPE_SIGNAL: