Lists with `ui.isHidden` resolving to `true` - route can still be accessed in the admin UI

[glennflanagan]

Reproduction steps

1. Create List with ui.isHidden function set to resolve to true. e.g.:

const User = list({
  ui: {
    isHidden: () => true,
  },
  fields: ...

2. See the list is hidden from the dasboard and navigation
3. Enter the route to the hidden list into the browser address bar e.g. http://localhost:3000/users and observe that you are directed to the list page.

Expected behaviour

Accessing the route of a list with ui.isHidden resolving to true should redirect the user back to the Dashboard