Fix error log printed when undeploying the devicemgt provider

Resolves https://github.com/wso2/product-iots/issues/1724

(cherry picked from commit c72d4ea)

components/device-mgt/org.wso2.carbon.device.mgt.core/src/main/java/org/wso2/carbon/device/mgt/core/DeviceManagementPluginRepository.java

@@ -23,6 +23,7 @@ import org.apache.commons.logging.LogFactory;
 import org.wso2.carbon.context.PrivilegedCarbonContext;
 import org.wso2.carbon.device.mgt.common.DeviceManagementException;
 import org.wso2.carbon.device.mgt.common.DeviceStatusTaskPluginConfig;
+import org.wso2.carbon.device.mgt.common.InvalidConfigurationException;
 import org.wso2.carbon.device.mgt.common.OperationMonitoringTaskConfig;
 import org.wso2.carbon.device.mgt.common.ProvisioningConfig;
 import org.wso2.carbon.device.mgt.common.operation.mgt.OperationManager;
@@ -153,10 +154,14 @@ public class DeviceManagementPluginRepository implements DeviceManagerStartupLis
         OperationManager operationManager = operationManagerRepository.getOperationManager(
                 deviceTypeIdentifier);
         if (operationManager != null) {
+            try {
                 NotificationStrategy notificationStrategy = operationManager.getNotificationStrategy();
                 if (notificationStrategy != null) {
                     notificationStrategy.undeploy();
                 }
+            } catch (InvalidConfigurationException ignore) {
+                //error occurred while undeploying strategy, ignore error
+            }
             operationManagerRepository.removeOperationManager(deviceTypeIdentifier);
         }
     }