[landing] added classnames dependency

Summary: added classnames dependency. This is so that we can use add conditional logic to Investor Profile Card Modal classes. We use this in the web codebase

Test Plan: N/A

Reviewers: ashoat, atul

Reviewed By: ashoat, atul

Subscribers: ashoat, tomek, atul, abosh

Differential Revision: https://phab.comm.dev/D5337