Add missing proto visitor for ClientState::is_sync_feature_enabled

This makes the field show up in the protocol log in sync-internals.

Bug: none
Change-Id: I04b4fec941ab5d1dae76b03d5b0aed27c55a82a0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1762241
Commit-Queue: Marc Treib <treib@chromium.org>
Commit-Queue: Jan Krcal <jkrcal@chromium.org>
Auto-Submit: Marc Treib <treib@chromium.org>
Reviewed-by: Jan Krcal <jkrcal@chromium.org>
Cr-Commit-Position: refs/heads/master@{#688628}

components/sync/protocol/proto_visitors.h

@@ -225,6 +225,7 @@ VISIT_PROTO_FIELDS(const sync_pb::ClientConfigParams& proto) {
 
 VISIT_PROTO_FIELDS(const sync_pb::ClientStatus& proto) {
   VISIT(hierarchy_conflict_detected);
+  VISIT(is_sync_feature_enabled);
 }
 
 VISIT_PROTO_FIELDS(const sync_pb::ClientToServerMessage& proto) {