Disclaimer needed on route quality and reminder not to use phone while cycling

[mvl22]

The iPhone and Android apps have a disclaimer to remind people that route quality cannot be guaranteed and that people should not use the phone while cycling (unless with a handlebar mount).

Similar text is needed for this app.

https://github.com/cyclestreets/ios/blob/fe52a4dc74e15ad77dc26df5f137512ede0f73e5/src/managers/RouteManager.m#L791

This is a one-time-only alert.

Maybe if the tutorial display setting were turned into a "Reset instructions" one-shot button, then this would also reset this warning.

[realworld666]

What point in the app does this warning appear?

[mvl22]

The time the user has planned a route, coming up as a dialog just as the route is displayed. They press OK, and from that point on it does not need to be shown again.