Typo fix

Author: colinl

ui/src/widgets/ui-chart/UIChart.vue

@@ -715,7 +715,7 @@ export default {
                 // ensure the data array exists
                 if (Array.isArray(options.series[sIndex].data) === false) {
                     options.series[sIndex].data = []
-                ]
+                }
                 if (this.props.xAxisType === 'category') {
                     // for categories, we need to update the existing data point for this x-value
                     const xIndex = options.series[sIndex].data.findIndex(d => d[0] === datapoint.x)