arc: Add Jelly flag to ArcChromeFeatureFlagsBridge

This CL adds a capability to propagate chrome://flags#jelly-colors in
ArcChromeFeatureFlagsBridge.
This CL also introduces the unified method (NotifyFeatureFlags()) to
propagate the multiple flags in a single method call.

Please note that currently no client implements
ChromeFeatureFlagsInstance it’s safe to delete the deprecated method.

BUG=b:285563577
TEST=ArcChromeFeatureFlagsBridgeTest

Change-Id: I92a4f7460f1f1c74dc3b92e5a01426b009e1106d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4584273
Reviewed-by: Yuichiro Hanada <yhanada@chromium.org>
Reviewed-by: Dominick Ng <dominickn@chromium.org>
Commit-Queue: Toshiki Kikuchi <toshikikikuchi@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1153740}