Fix order in monthly events boundary query

Upper boundary for monthly rage of manage events Service Ping metric
was using wrong ordering, resulting in to small range being selected

Changelog: fixed

lib/gitlab/usage_data.rb

@@ -727,7 +727,7 @@ module Gitlab
           # rubocop: disable CodeReuse/ActiveRecord
           # rubocop: disable UsageData/LargeTable
           start = ::Event.where(time_period).select(:id).order(created_at: :asc).first&.id
-          finish = ::Event.where(time_period).select(:id).order(created_at: :asc).first&.id
+          finish = ::Event.where(time_period).select(:id).order(created_at: :desc).first&.id
           estimate_batch_distinct_count(::Event.where(time_period), :author_id, start: start, finish: finish)
           # rubocop: enable UsageData/LargeTable
           # rubocop: enable CodeReuse/ActiveRecord

spec/lib/gitlab/usage_data_spec.rb

@@ -199,7 +199,6 @@ RSpec.describe Gitlab::UsageData, :aggregate_failures do
       for_defined_days_back do
         user = create(:user)
         user2 = create(:user)
-        create(:event, author: user)
         create(:group_member, user: user)
         create(:authentication_event, user: user, provider: :ldapmain, result: :success)
         create(:authentication_event, user: user2, provider: :ldapsecondary, result: :success)
@@ -208,17 +207,24 @@ RSpec.describe Gitlab::UsageData, :aggregate_failures do
         create(:authentication_event, user: user, provider: :group_saml, result: :failed)
       end
 
+      for_defined_days_back(days: [31, 29, 3]) do
+        create(:event)
+      end
+
+      stub_const('Gitlab::Database::PostgresHll::BatchDistinctCounter::DEFAULT_BATCH_SIZE', 1)
+      stub_const('Gitlab::Database::PostgresHll::BatchDistinctCounter::MIN_REQUIRED_BATCH_SIZE', 0)
+
       expect(described_class.usage_activity_by_stage_manage({})).to include(
         events: -1,
         groups: 2,
-        users_created: 6,
+        users_created: 10,
         omniauth_providers: ['google_oauth2'],
         user_auth_by_provider: { 'group_saml' => 2, 'ldap' => 4, 'standard' => 0, 'two-factor' => 0, 'two-factor-via-u2f-device' => 0, "two-factor-via-webauthn-device" => 0 }
       )
       expect(described_class.usage_activity_by_stage_manage(described_class.monthly_time_range_db_params)).to include(
-        events: be_within(error_rate).percent_of(1),
+        events: be_within(error_rate).percent_of(2),
         groups: 1,
-        users_created: 3,
+        users_created: 6,
         omniauth_providers: ['google_oauth2'],
         user_auth_by_provider: { 'group_saml' => 1, 'ldap' => 2, 'standard' => 0, 'two-factor' => 0, 'two-factor-via-u2f-device' => 0, "two-factor-via-webauthn-device" => 0 }
       )