[web] [fix] benjamin/eng-896-color-splotch-wrong-size-currently-40px

Summary:
Size bar color splotch is the wrong size https://linear.app/comm/issue/ENG-896/color-splotch-wrong-size-currently-40px-should-be-42px more in linear

before:

after:

Test Plan: Make it match figma at 42px

Reviewers: atul, palys-swm, def-au1t

Reviewed By: palys-swm

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

Differential Revision: https://phabricator.ashoat.com/D3455