[web] introduce light mode to danger zone component

Summary:
This diff introduces the new color design system/light mode to the danger zone component

For additional context about this new color design system and the new naming convention here is the notion doc, @ted and I wrote:
https://www.notion.so/commapp/New-Color-System-Proposal-ef80b4e4b9ec42949095056161223a42

Here is the WIP spreadsheet @ted and I have been using as our source of truth of what we should use as color variables and their associated values
https://docs.google.com/spreadsheets/d/1PwdxT8Ag_4AGzmGSj2wXsR5-go9rsgZvTZycpy3e49k/edit#gid=0

Linear task: https://linear.app/comm/issue/ENG-4803/danger-zone

Depends on D9582

Test Plan:
Please see the screenshots below

dark:

light:

Reviewers: atul, inka, rohan

Reviewed By: atul

Subscribers: ashoat, tomek, ted, wyilio

Differential Revision: https://phab.comm.dev/D9583