[DJM-814] Set intaller span tag to true only when len > 0 (#36744)

Author: aboitreaud

pkg/fleet/installer/setup/djm/databricks.go

@@ -208,7 +208,11 @@ func setClearIfExists(s *common.Setup, envKey, tagKey string, normalize func(str
 
 func setHostTag(s *common.Setup, tagKey, value string) {
 	s.Config.DatadogYAML.Tags = append(s.Config.DatadogYAML.Tags, tagKey+":"+value)
-	s.Span.SetTag("host_tag_set."+tagKey, "true")
+	isTagPresent := "false"
+	if value != "" {
+		isTagPresent = "true"
+	}
+	s.Span.SetTag("host_tag_set."+tagKey, isTagPresent)
 }
 
 func setClearHostTag(s *common.Setup, tagKey, value string) {