feat: add SearchParams types to Expo Router

[marklawlor]

Why

useLocalSearchParams in currently typed. We can not generate a helper type to convert a route to the SearchParams objects

These types are strongly connected to the generated routes and will break if a route ever changes (e.g the variable is renamed).

Relative routes are ignores and are currently considered out of scope.

// These are expected to return an empty object as there are no search parameters
SearchParams<"/">
// ^? {}
SearchParams<"/test">
// ^? {}

SearchParams<"/user/[id]">
// ^? { id: string }
SearchParams<"/team/[...id]">
// ^? { id: string[] }

One annoying downside is that the autocomplete doesn't work. This due to typescript simply not supporting it microsoft/TypeScript#34771