[web] Deleted unused file

Summary:
We don't use this file. We use color-selector instead.
Deleted it and related css.

Test Plan:
Tested if app runs.
Tested if color picking in thread works.

Reviewers: tomek, kamil, atul

Reviewed By: tomek

Subscribers: ashoat, atul, kamil, tomek

Differential Revision: https://phab.comm.dev/D5800