SmartUrlInput: Fix Object pseudotypes, and a type error they hid.
SmartUrlInput: Fix Object pseudotypes, and a type error they hid.

This is another example where `mixed` is a good way to express
"no assumptions at all" -- this component doesn't expect anything
in particular from the nav state described by the generic parameter,
just needs the `navigation` prop in order to call `addListener`.

vishwesh3/zulip-mobile,vishwesh3/zulip-mobile,vishwesh3/zulip-mobile,vishwesh3/zulip-mobile