CSP nonces not applied

LiveDashboard has a [`:csp_nonce_assign_key` option ](https://hexdocs.pm/phoenix_live_dashboard/Phoenix.LiveDashboard.Router.html#live_dashboard/2-options), but it appears that flame_on doesn't apply it.

<img width="1028" alt="image" src="https://github.com/DockYard/flame_on/assets/13847569/180d50f9-31c9-41b2-aff5-1f2a6cdd23fe">