When you say you see an air bubble in the spigot, are you talking about inside the bucket, or the red part on the outside? If it's inside the bucket I wouldn't worry about it, since it's most likely CO2 anyways. If it's on the outside, well, it's not touching the beer so don't worry about it.
Do you have another bucket you can rack the beer to? It would be best to get it off the trub since you have to mix in the bottling sugar and it will stir up all that crap on the bottom when you do. Siphon (not pour) the beer to another bucket, clean the bucket with spigot out, rack back into bottling bucket, bottle, then wait 3 weeks and enjoy!