[web] [remove] no longer use "react-entypo-icons"

Summary: remove package, icons aren't used in the project

Test Plan: make sure app doesn't crash

Reviewers: atul, ashoat

Reviewed By: atul, ashoat

Subscribers: ashoat, palys-swm, Adrian, karol-bisztyga

Differential Revision: https://phabricator.ashoat.com/D3096