FR better mod-switching campaign handling

Every time you switch between two mods with different campaigns on the same pilot you need to pick the campaign you want to play. It seems to me this should only be needed when you haven't ever played that mod with that pilot before, and when there's more than one campaign available. If there's only one campaign then we should just auto-select that one, since that's all the player can do anyway. And we should be able to save the last chosen campaign a pilot played for each mod so they can go back to that one if there's multiple.

Any reason we couldn't/shouldn't do that?