Silence reroute questioning if reroute is already inflight

[JThramer]

Quick fix. Implements #1929.

/cc @mapbox/navigation-ios

[akitchen]

Are commas considered more idiomatic than && ? The mix of commas and ?? is weird to read at first, but LGTM

[JThramer]

@akitchen I generally try and use commas if there are exclusively AND statements in the clause ("This, that, and the other"), and use explicit boolean notation if the clause is more complex. ("This and that, but not those or this other thing.")