kvserver: metamorphically enable kv.closed_timestamp.lead_for_global_reads_auto_tune.enabled

This commit metamorphically enables
kv.closed_timestamp.lead_for_global_reads_auto_tune.enabled.

Part of: #143888
Release note: none

Author: wenyihu6

pkg/kv/kvserver/closedts/BUILD.bazel

@@ -13,6 +13,7 @@ go_library(
         "//pkg/kv/kvserver/closedts/ctpb",
         "//pkg/settings",
         "//pkg/util/hlc",
+        "//pkg/util/metamorphic",
     ],
 )
 

pkg/kv/kvserver/closedts/setting.go

@@ -9,6 +9,7 @@ import (
 	"time"
 
 	"github.com/cockroachdb/cockroach/pkg/settings"
+	"github.com/cockroachdb/cockroach/pkg/util/metamorphic"
 )
 
 // NB: These settings are SystemVisible because they need to be read by e.g.
@@ -86,6 +87,6 @@ var LeadForGlobalReadsAutoTuneEnabled = settings.RegisterBoolSetting(
 		"furthest follower will be used to adjust closed timestamp policies for ranges"+
 		"ranges configured to serve global reads. "+
 		"kv.closed_timestamp.lead_for_global_reads_override takes precedence if set.",
-	false,
+	metamorphic.ConstantWithTestBool("kv.closed_timestamp.lead_for_global_reads_auto_tune.enabled", false),
 	settings.WithPublic,
 )