PropertyInfo: Only include 'usage' in Dictionary conversion when explicitly set

[TheAenema]

The implicit conversion from PropertyInfo to Dictionary currently includes the usage field unconditionally.

In recent Godot versions, support for the usage field has been removed from add_property_info() for both EditorSettings and ProjectSettings triggering the following warning whenever PropertyInfo is used:

WARNING: "usage" is not supported in add_property_info().

This causes unnecessary warning spam in the editor console when registering custom settings from GDExtension using PropertyInfo.

Fix is quite simple, We add a check in PropertyInfo::operator Dictionary() that assigns the usage field only when it's set to a value other than PROPERTY_USAGE_NONE.

operator Dictionary() const {
	Dictionary dict;
	dict["name"] = name;
	dict["class_name"] = class_name;
	dict["type"] = type;
	dict["hint"] = hint;
	dict["hint_string"] = hint_string;
	if (usage != PROPERTY_USAGE_NONE) {
		dict["usage"] = usage;
	}
	return dict;
}

[dsnopek]

Thanks! That makes sense to me :-)