Merge branch 'fix-broadcast-message-factory-date-range' into 'master'

TST: Use more accurate time windows so tests do not fail

This MR sets the Datetime attributes of the of the broadcast messages factory more precisely. 

This MR is necessary to ensure that all specs which use the broadcast message factory will pass when run anywhere at any time. Currently, the way the 'starts_at' and 'ends_at' attributes are set,if the specs are run at one second to midnight, the broadcast message will expire in one second. I have changed it so that we are guaranteed a period of one day until expiration. I believe this is the desired behaviour and it's also consistent with the rest of the factory. 

See merge request !5674

spec/factories/broadcast_messages.rb

 FactoryGirl.define do
   factory :broadcast_message do
     message "MyText"
-    starts_at Date.yesterday
-    ends_at Date.tomorrow
+    starts_at 1.day.ago
+    ends_at 1.day.from_now
 
     trait :expired do
       starts_at 5.days.ago