Fixing the case where multiple tags were passed for searching the APIs.

components/apimgt-extensions/org.wso2.carbon.apimgt.application.extension/src/main/java/org/wso2/carbon/apimgt/application/extension/APIManagementProviderServiceImpl.java

@@ -153,7 +153,9 @@ public class APIManagementProviderServiceImpl implements APIManagementProviderSe
                             subscription.setApiIdentifier(id);
                             subscription.setApplicationId(application.getApplicationId());
                             subscription.tier(ApiApplicationConstants.DEFAULT_TIER);
-                            needToSubscribe.add(subscription);
+                            if (!needToSubscribe.contains(subscription)){
+                                needToSubscribe.add(subscription);
+                            }
                         }
                     }
                 }