### 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<Signal>::variant_from_type;
		case GDEXTENSION_VARIANT_TYPE_DICTIONARY:
			return VariantTypeConstructor<Dictionary>::variant_from_type;
		case GDEXTENSION_VARIANT_TYPE_ARRAY:
			return VariantTypeConstructor<Array>::variant_from_type;
		case GDEXTENSION_VARIANT_TYPE_PACKED_BYTE_ARRAY:
			return VariantTypeConstructor<PackedByteArray>::variant_from_type;
		case GDEXTENSION_VARIANT_TYPE_PACKED_INT32_ARRAY:
			return VariantTypeConstructor<PackedInt32Array>::variant_from_type;
		case GDEXTENSION_VARIANT_TYPE_PACKED_INT64_ARRAY:
			return VariantTypeConstructor<PackedInt64Array>::variant_from_type;
		case GDEXTENSION_VARIANT_TYPE_PACKED_FLOAT32_ARRAY:
			return VariantTypeConstructor<PackedFloat32Array>::variant_from_type;
		case GDEXTENSION_VARIANT_TYPE_PACKED_FLOAT64_ARRAY:
			return VariantTypeConstructor<PackedFloat64Array>::variant_from_type;
		case GDEXTENSION_VARIANT_TYPE_PACKED_STRING_ARRAY:
			return VariantTypeConstructor<PackedStringArray>::variant_from_type;
		case GDEXTENSION_VARIANT_TYPE_PACKED_VECTOR2_ARRAY:
			return VariantTypeConstructor<PackedVector2Array>::variant_from_type;
		case GDEXTENSION_VARIANT_TYPE_PACKED_VECTOR3_ARRAY:
			return VariantTypeConstructor<PackedVector3Array>::variant_from_type;
		case GDEXTENSION_VARIANT_TYPE_PACKED_COLOR_ARRAY:
			return VariantTypeConstructor<PackedColorArray>::variant_from_type;
		case GDEXTENSION_VARIANT_TYPE_NIL:
		case GDEXTENSION_VARIANT_TYPE_VARIANT_MAX:
			ERR_FAIL_V_MSG(nullptr, "Getting Variant conversion function with invalid type");
	}
	ERR_FAIL_V_MSG(nullptr, "Getting Variant conversion function with invalid type");
}
static GDExtensionTypeFromVariantConstructorFunc gdextension_get_variant_to_type_constructor(GDExtensionVariantType p_type) {