typing: appease pyright and disable mypy unusued import warning

typing: appease pyright and disable mypy unusued import warning

Since pyright reuses the same comments to ignore types, one can get into
unsatisfiable situations, where one type checker accepts something but the other
doesn't. At this point we only have three instances of type ignore hints anyway,
sol et's relax our mypy settings somewhat, so that we can shut up pyright, when
necessary.