fix line charts stepped line
fix line charts stepped line

fix(sample):fix line charts stepped line

fixes
https://github.com/aurelia-ui-toolkits/aurelia-kendoui-plugin/issues/194

smccrea/aurelia-kendoui-plugin,aurelia-ui-toolkits/aurelia-kendoui-plugin,aurelia-ui-toolkits/aurelia-kendoui-bridge,aurelia-ui-toolkits/aurelia-kendoui-plugin,smccrea/aurelia-kendoui-plugin,aurelia-ui-toolkits/aurelia-kendoui-bridge