[web] introduce navigation sidebar tooltip

Summary:
This diff introduces the navigation sidebar tooltip

For context here is what this looks like on the figma:

Part of https://linear.app/comm/issue/ENG-5948/hovering-over-every-clickable-element-in-this-sidebar-will-have-a

Depends on D10349

Test Plan:
Please see screenshot below

Reviewers: atul, rohan, kamil

Reviewed By: rohan

Subscribers: ashoat, tomek

Differential Revision: https://phab.comm.dev/D10350