Resolve "Update comment icons and add Duo Chat"

See merge request gitlab-org/gitlab-svgs!1073



Merged-by: Julia Miocene <jmiocene@gitlab.com>
Approved-by: Julia Miocene <jmiocene@gitlab.com>
Co-authored-by: Jeremy Elder <jelder@gitlab.com>

# [3.110.0]
## Changes
  - Added icon 'duo-chat-off'
  - Added icon 'duo-chat'
  - Updated icon 'comment-dots'
  - Updated icon 'comment-lines'
  - Updated icon 'comment-next'
  - Updated icon 'comment'