[1/n] Native Typeahead - Moving type decalration to lib

Summary:
We can use the same type both in web and native logic.
Thus moving it to shared typeahead utils.

Test Plan: Checked if web app still works

Reviewers: inka, ginsu, kamil, michal, tomek

Reviewed By: inka, tomek

Subscribers: ashoat, tomek, atul, michal, kamil, ginsu, inka

Differential Revision: https://phab.comm.dev/D6297