Allow explicit metric registration. Fixes #11732 (#27966)

* Register ha timing metrics. Fixes #11732

* Add CHANGELOG

* Fix copywrite headers

* Relicence SDK files after move

* Update vault/ha.go

internalshared/configutil/telemetry.go

@@ -22,6 +22,7 @@ import (
 	"github.com/hashicorp/hcl"
 	"github.com/hashicorp/hcl/hcl/ast"
 	"github.com/hashicorp/vault/helper/metricsutil"
+	"github.com/hashicorp/vault/sdk/helper/metricregistry"
 	"google.golang.org/api/option"
 )
 
@@ -289,6 +290,10 @@ func SetupTelemetry(opts *SetupTelemetryOpts) (*metrics.InmemSink, *metricsutil.
 			Expiration: opts.Config.PrometheusRetentionTime,
 		}
 
+		// Merge in explicit metric definitions so Prometheus always reports those
+		// metrics.
+		metricregistry.MergeDefinitions(&prometheusOpts)
+
 		sink, err := prometheus.NewPrometheusSinkFrom(prometheusOpts)
 		if err != nil {
 			return nil, nil, false, err