Update snapshots for latest vue-test-utils

These snapshots were created before `vue-test-utils` was updated in
https://gitlab.com/gitlab-org/gitlab/merge_requests/22462, which changed
slightly how snapshots are formatted.

ee/spec/frontend/threat_monitoring/components/__snapshots__/waf_statistics_summary_spec.js.snap

 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`WafStatisticsSummary component renders the anomalous traffic percentage 1`] = `
-<glsinglestat-stub
+<gl-single-stat-stub
   class="col-sm-6 col-md-4 col-lg-3"
   title="Anomalous Requests"
   value="3%"
@@ -10,7 +10,7 @@ exports[`WafStatisticsSummary component renders the anomalous traffic percentage
 `;
 
 exports[`WafStatisticsSummary component renders the nominal traffic count 1`] = `
-<glsinglestat-stub
+<gl-single-stat-stub
   class="col-sm-6 col-md-4 col-lg-3"
   title="Total Requests"
   value="2.7k"