Yeah it's not the most intuitive process. Funny thing is it's not actually the first time I've done that, the issue was that I named my dictionary files as .dat files (I have no idea why, maybe I'm just a little old school) and I didn't realise I would have to white list the file extension for Godot to package the dictionaries in with the assets. So the game actually uploaded pretty much okay, but because there were no dictionaries, no words were valid! That took me quite a while to figure out...