Fix telemetry client enable configuration

Author: Flanker32

Utils/azuretools-core/src/com/microsoft/azuretools/telemetry/AppInsightsClient.java

@@ -176,6 +176,7 @@ private static boolean isAppInsightsClientAvailable() {
     private static void initTelemetryManager() {
         try {
             final Map<String, String> properties = buildProperties("", new HashMap<>());
+            TelemetryClientSingleton.setConfiguration(configuration);
             final TelemetryClient client = TelemetryClientSingleton.getTelemetry();
             final String eventNamePrefix = configuration.eventName();
             TelemetryManager.getInstance().setTelemetryClient(client);
@@ -188,5 +189,4 @@ private static void initTelemetryManager() {
         } catch (Exception ignore) {
         }
     }
-
 }

Utils/azuretools-core/src/com/microsoft/azuretools/telemetry/TelemetryClientSingleton.java

@@ -4,20 +4,35 @@
  */
 
 package com.microsoft.azuretools.telemetry;
+
 import com.microsoft.applicationinsights.TelemetryClient;
+import org.apache.commons.lang3.StringUtils;
 
 public final class TelemetryClientSingleton {
     private TelemetryClient telemetry = null;
+    private AppInsightsConfiguration configuration = null;
 
     private static final class SingletonHolder {
         private static final TelemetryClientSingleton INSTANCE = new TelemetryClientSingleton();
     }
 
-    public static TelemetryClient getTelemetry(){
+    public static TelemetryClient getTelemetry() {
         return SingletonHolder.INSTANCE.telemetry;
     }
 
-    private TelemetryClientSingleton(){
-        telemetry = new TelemetryClient();
+    public static void setConfiguration(final AppInsightsConfiguration configuration) {
+        SingletonHolder.INSTANCE.configuration = configuration;
+    }
+
+    private TelemetryClientSingleton() {
+        telemetry = new TelemetryClient() {
+            @Override
+            public boolean isDisabled() {
+                if (configuration == null) {
+                    return true;
+                }
+                return (StringUtils.isNotEmpty(configuration.preferenceVal()) && !Boolean.valueOf(configuration.preferenceVal())) || super.isDisabled();
+            }
+        };
     }
 }