[#1531] metrics: Rename app_info metric

Signed-off-by: Ekaterina Lebedeva <ekaterina.lebedeva@yadro.com>

internal/metrics/application.go

@@ -12,6 +12,7 @@ type ApplicationInfo struct {
 func NewApplicationInfo(version string) *ApplicationInfo {
 	appInfo := &ApplicationInfo{
 		versionValue: metrics.NewGaugeVec(prometheus.GaugeOpts{
+			Namespace: namespace,
 			Name:      "app_info",
 			Help:      "General information about the application.",
 		}, []string{"version"}),