Changing URL (and therefore react-router params) does not refresh child components

I am splitting this off from LIBAPP-147, as that one has wandered into deep Stripes-Connect territory rather than being about a library application. (I should really have done this some time ago.)

The problem here is that when <ViewUsers>, which is itself a child component of <Users>, includes <UserPermissions>, that does not refresh itself when the URL changes, which means that it continues to display the permissions of the first user that was displayed ever after the rest of the application has moved onto another user.

We can "fix" this by passing all of the <ViewUsers> props down, as <UserPermissions {...this.props} />, which allows us to close LIBAPP-147; but this is not getting to the root of the problem.