CrOS Settings: Remove Jelly flag

Jelly has launched and the Jelly flag can be removed. Dependent code
no longer requires the Jelly flag.

Bug: b:319740292
Test: Manually verify dynamic colors supported
Change-Id: I31ae61bb15d0de0cf3104a1355a4f4289cf6c6a0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5426053


Reviewed-by: Xiaohui Chen <xiaohuic@chromium.org>
Commit-Queue: Wes Okuhara <wesokuhara@google.com>
Cr-Commit-Position: refs/heads/main@{#1283370}