[web,native] [chore] [ENG-1032] add covariant declarations to props that were missing

Summary: https://linear.app/comm/issue/ENG-1032/add-missing-covariant-declarations-in-web-and-native

Test Plan: run flow on native and web adding @ashoat as a reviewer because this was initially a comment of D3811

Reviewers: atul, palys-swm, ashoat, def-au1t, yayabosh

Reviewed By: ashoat

Subscribers: Adrian, karol-bisztyga, ashoat

Differential Revision: https://phabricator.ashoat.com/D3816