Fix flaky test failure in charts_spec

The timezone based tests in ci/charts_spec will
fail when executed close to midnight, as witnessed
in https://gitlab.com/gitlab-org/gitlab/-/jobs/1019524415

This change addresses the stability of the test by
specifying an explicit time for an object that is being
queried in a sensitive time window

This is a follow-up fix for just the tests originally added
via https://gitlab.com/gitlab-org/gitlab/-/merge_requests/52971

spec/lib/gitlab/ci/charts_spec.rb

@@ -98,7 +98,12 @@ RSpec.describe Gitlab::Ci::Charts do
     subject { chart.total }
 
     before do
-      create(:ci_empty_pipeline, project: project, duration: 120)
+      # The created_at time used by the following execution
+      # can end up being after the creation of the 'today' time
+      # objects created above, and cause the queried counts to
+      # go to zero when the test executes close to midnight on the
+      # CI system, so we explicitly set it to a day earlier
+      create(:ci_empty_pipeline, project: project, duration: 120, created_at: today - 1.day)
     end
 
     it 'uses a utc time zone for range times' do