Bluesky -> *: Accept DID argument in DM commands

[tesaguri]

Some DM commands take a handle as an argument, but not all Bluesky users have a valid handle. If such a user were abusive, that means you cannot block that user from other networks. So I think it would be helpful if DM commands (especially block) allow specifying users by DIDs.

[snarfed]

Great point! Absolutely right, thanks for the nudge, will do.