Fix flaky VSA tests

- Make sure issue creation happens within rubocop freeze.
- Make sure the time part of endDate is at the end of the day.

ee/app/assets/javascripts/analytics/cycle_analytics/utils.js

@@ -193,9 +193,12 @@ export const getDurationChartData = (data, startDate, endDate) => {
   const flattenedData = flattenDurationChartData(data);
   const eventData = [];
 
+  const endOfDay = newDate(endDate);
+  endOfDay.setHours(23, 59, 59); // make sure we're at the end of the day
+
   for (
     let currentDate = newDate(startDate);
-    currentDate <= endDate;
+    currentDate <= endOfDay;
     currentDate = dayAfter(currentDate)
   ) {
     const currentISODate = dateFormat(newDate(currentDate), dateFormats.isoDate);

ee/spec/features/groups/analytics/cycle_analytics/filters_and_data_spec.rb

@@ -281,13 +281,14 @@ RSpec.describe 'Group value stream analytics filters and data', :js do
   end
 
   context 'with lots of data', :js do
-    let_it_be(:issue) { create(:issue, project: project, created_at: 5.days.ago) }
+    let_it_be(:issue) { create(:issue, project: project) }
 
     around do |example|
       freeze_time { example.run }
     end
 
     before do
+      issue.update!(created_at: 5.days.ago)
       create_cycle(user, project, issue, mr, milestone, pipeline)
       create(:labeled_issue, created_at: 5.days.ago, project: create(:project, group: group), labels: [group_label1])
       create(:labeled_issue, created_at: 3.days.ago, project: create(:project, group: group), labels: [group_label2])