Add no_disclosed_vendors metric

Author: CTMBNara

src/main/java/org/prebid/server/metric/MetricName.java

@@ -104,6 +104,7 @@ public enum MetricName {
     specified,
     opt_out("opt-out"),
     invalid,
+    no_disclosed_vendors("no-disclosed-vendors"),
     in_geo("in-geo"),
     out_geo("out-geo"),
     unknown_geo("unknown-geo"),

src/main/java/org/prebid/server/metric/Metrics.java

@@ -519,6 +519,10 @@ public void updatePrivacyTcfInvalidMetric() {
         privacy().tcf().incCounter(MetricName.invalid);
     }
 
+    public void updatePrivacyTcfNoDisclosedVendorsMetric() {
+        privacy().tcf().incCounter(MetricName.no_disclosed_vendors);
+    }
+
     public void updatePrivacyTcfRequestsMetric(int version) {
         final UpdatableMetrics versionMetrics = privacy().tcf().fromVersion(version);
         versionMetrics.incCounter(MetricName.requests);

src/main/java/org/prebid/server/privacy/gdpr/TcfDefinerService.java

@@ -352,7 +352,7 @@ private TCStringParsingResult parseConsentString(String consentString, RequestLo
             final String message = "Invalid TCF string: `disclosedVendors` list is empty.";
             warnings.add(message);
             logWarn(consentString, message, requestLogInfo);
-            metrics.updatePrivacyTcfInvalidMetric();
+            metrics.updatePrivacyTcfNoDisclosedVendorsMetric();
 
             return TCStringParsingResult.of(TCStringEmpty.create(), warnings);
         }

src/test/java/org/prebid/server/privacy/gdpr/TcfDefinerServiceTest.java

@@ -571,7 +571,7 @@ public void resolveTcfContextShouldIncrementInvalidConsentStringMetricWhenDisclo
             assertThat(context.getWarnings()).containsExactly("Invalid TCF string: `disclosedVendors` list is empty.");
         });
 
-        verify(metrics).updatePrivacyTcfInvalidMetric();
+        verify(metrics).updatePrivacyTcfNoDisclosedVendorsMetric();
     }
 
     @Test