Merge branch 'adriel-security-dashboard-no-chart-theme' into 'master'

Disable echarts theme on security dashboard

See merge request gitlab-org/gitlab-ee!9812

ee/app/assets/javascripts/security_dashboard/components/vulnerability_chart.vue

@@ -186,7 +186,7 @@ export default {
 
     <div class="vulnerabilities-chart">
       <div class="vulnerabilities-chart-wrapper">
-        <gl-chart :options="options" />
+        <gl-chart :options="options" :disable-theme="true" />
         <chart-tooltip
           v-show="false"
           ref="tooltip"