Update callers of HistoricalData to pass in Time as parameters

Previously, `HistoricalData.date` was a `date`. When doing date range
calculations such as `HistoricalData.where(
Date.parse('2020-10-20')..Date.parse('2020-10-23'))`, any records
containing 20th or 23rd are included in the result.

However, with `HistoricalData.date` as a timestamp with time zone,
20th would be included (since the time component is assumed to be 00:00)
but 23rd would be excluded.

In order to include both days, we need to use
`.beginning_of_day` and `.end_of_day`. Both methods are time zone aware
and will use the `Time.zone` if available.

ee/app/models/gitlab/seat_link_data.rb

@@ -38,8 +38,8 @@ module Gitlab
 
     def default_max_count(date)
       HistoricalData.max_historical_user_count(
-        from: ::License.current.starts_at,
-        to: date
+        from: ::License.current.starts_at.beginning_of_day,
+        to: date.end_of_day
       )
     end
 

ee/app/models/historical_data.rb

@@ -23,16 +23,16 @@ class HistoricalData < ApplicationRecord
 
     def max_historical_user_count(license: nil, from: nil, to: nil)
       license ||= License.current
-      expires_at = license&.expires_at || Date.today
-      from ||= expires_at - 1.year
-      to   ||= expires_at
+      expires_at = license&.expires_at || Time.current
+      from ||= (expires_at - 1.year).beginning_of_day
+      to   ||= expires_at.end_of_day
 
       HistoricalData.during(from..to).maximum(:active_user_count) || 0
     end
 
     def in_license_term(license)
-      start_date = license.starts_at
-      expiration_date = license.expires_at || Date.current
+      start_date = license.starts_at.beginning_of_day
+      expiration_date = license.expires_at&.end_of_day || Time.current
 
       HistoricalData.during(start_date..expiration_date)
     end

ee/app/models/license.rb

@@ -550,8 +550,8 @@ class License < ApplicationRecord
 
   def prior_historical_max
     @prior_historical_max ||= begin
-      from = starts_at - 1.year
-      to   = starts_at
+      from = (starts_at - 1.year).beginning_of_day
+      to   = starts_at.end_of_day
 
       historical_max(from, to)
     end
@@ -573,8 +573,8 @@ class License < ApplicationRecord
 
   def check_trueup
     trueup_qty          = restrictions[:trueup_quantity]
-    trueup_from         = Date.parse(restrictions[:trueup_from]) rescue (starts_at - 1.year)
-    trueup_to           = Date.parse(restrictions[:trueup_to]) rescue starts_at
+    trueup_from         = Date.parse(restrictions[:trueup_from]).beginning_of_day rescue (starts_at - 1.year).beginning_of_day
+    trueup_to           = Date.parse(restrictions[:trueup_to]).end_of_day rescue starts_at.end_of_day
     max_historical      = historical_max(trueup_from, trueup_to)
     expected_trueup_qty = if previous_user_count
                             max_historical - previous_user_count