[web] Introduce large variant of ColorSelector

Summary:
In this diff we introduce size prop to ColorSelector component and implement styling/layout for large variant.

This is for use in the EmojiAvatarSelection component.

Test Plan:
Here's how it looks:

Also ensured that other usages of ColorSelector in web continue to appear as expected (eg ThreadSettings)

Reviewers: ashoat, ginsu, rohan

Reviewed By: rohan

Subscribers: tomek

Differential Revision: https://phab.comm.dev/D8313