Device credential value can be null

@@ -77,7 +77,7 @@ public class DeviceMsgConstructor {
                     .setCredentialsId(deviceCredentials.getCredentialsId());
         }
         if (deviceCredentials.getCredentialsValue() != null) {
-            builder.setCredentialsValue(deviceCredentials.getCredentialsValue());
+            builder.setCredentialsValue(getStringValue(deviceCredentials.getCredentialsValue()));
         }
         return builder.build();
     }

@@ -144,7 +144,9 @@ public class DeviceEdgeProcessor extends BaseEdgeProcessor {
                     DeviceCredentials deviceCredentials = deviceCredentialsService.findDeviceCredentialsByDeviceId(tenantId, device.getId());
                     deviceCredentials.setCredentialsType(DeviceCredentialsType.valueOf(deviceCredentialsUpdateMsg.getCredentialsType()));
                     deviceCredentials.setCredentialsId(deviceCredentialsUpdateMsg.getCredentialsId());
-                    deviceCredentials.setCredentialsValue(deviceCredentialsUpdateMsg.getCredentialsValue());
+                    if (deviceCredentialsUpdateMsg.hasCredentialsValue()) {
+                        deviceCredentials.setCredentialsValue(deviceCredentialsUpdateMsg.getCredentialsValue().getValue());
+                    }
                     deviceCredentialsService.updateDeviceCredentials(tenantId, deviceCredentials);
                 } catch (Exception e) {
                     log.error("Can't update device credentials for device [{}], deviceCredentialsUpdateMsg [{}]", device.getName(), deviceCredentialsUpdateMsg, e);

@@ -219,7 +219,7 @@ message DeviceCredentialsUpdateMsg {
   int64 deviceIdLSB = 2;
   string credentialsType = 3;
   string credentialsId = 4;
-  string credentialsValue = 5;
+  google.protobuf.StringValue credentialsValue = 5;
 }
 
 message AssetUpdateMsg {