Remove chronos from audio group

chronos should use audio devices via CRAS instead of directly accessing
alsa, so remove it from the audio group.

BUG=chromium:216640
TEST=Verified that the alsa test in tast and autotest still can be passed.

Cq-Depend: chromium:1824784
Change-Id: Id07ab690575486ad8679101d1e67fa91127cf31b
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/overlays/eclass-overlay/+/1802062
Reviewed-by: Shuhei Takahashi <nya@chromium.org>
Reviewed-by: Cheng-Yi Chiang <cychiang@chromium.org>
Reviewed-by: Allen Webb <allenwebb@google.com>
Tested-by: Yu-Hsuan Hsu <yuhsuan@chromium.org>
Commit-Queue: Yu-Hsuan Hsu <yuhsuan@chromium.org>
diff --git a/profiles/base/accounts/group/audio b/profiles/base/accounts/group/audio
index 739276b..0f40539 100644
--- a/profiles/base/accounts/group/audio
+++ b/profiles/base/accounts/group/audio
@@ -1,3 +1,3 @@
 group:audio
 gid:18
-users:cras,chronos,volume,midis,rtanalytics
+users:cras,volume,midis,rtanalytics