Controlling the expanded state allows us to close the collapse after
items are selected (as recommended by react-bootstrap maintainers).
Also makes changes to the nav components to pass through props
(required by react-bootstrap to correctly wire everything together).
The disabling only happens when the piece list is fetched, which may
not happen immediately in some cases (ie. logged in user goes straight
to another person’s edition first). We’re not able to fetch the piece
list immediately, as some white labels apply default filters on the
piece list which forces them to wait until they can begin fetching
their piece lists.
