CI on 5c2011e6 caught it: removing the MiniPlayer kebab also removed
the only consumer of ShellScaffold's navController parameter, which
detekt's UnusedParameter rule flagged. Per YAGNI, dropping the param
entirely instead of @Suppress'ing a dead carry; if a future banner
or shell-level affordance needs nav, plumb it back in at that point.
Touches the public signature so all 10+ call sites in MinstrelNavGraph
also lose the `navController = navController` argument.
bvandeusen
eb4537c013