Deprecate monthly incident_sla_enabled metric

doc/development/usage_ping/dictionary.md

@@ -4354,6 +4354,8 @@ The total count of Helm packages that have been published.
 
 Group: `group::package`
 
+Data Category: `Optional`
+
 Status: `implemented`
 
 Tiers: `free`, `premium`, `ultimate`
@@ -22264,7 +22266,7 @@ Group: `group::monitor`
 
 Data Category: `Optional`
 
-Status: `data_available`
+Status: `deprecated`
 
 Tiers: `premium`, `ultimate`
 

ee/config/metrics/counts_all/20210216183753_projects_incident_sla_enabled.yml

@@ -7,7 +7,7 @@ product_stage:
 product_group: group::monitor
 product_category: metrics
 value_type: number
-status: data_available
+status: deprecated
 time_frame: all
 data_source: database
 distribution:

ee/lib/ee/gitlab/usage_data.rb

@@ -320,7 +320,7 @@ module EE
         def usage_activity_by_stage_monitor(time_period)
           super.merge({
             operations_dashboard_users_with_projects_added: distinct_count(UsersOpsDashboardProject.joins(:user).merge(::User.active).where(time_period), :user_id),
-            projects_incident_sla_enabled: count(::Project.with_enabled_incident_sla)
+            projects_incident_sla_enabled: time_period.present? ? ::Gitlab::UsageData::DEPRECATED_VALUE : count(::Project.with_enabled_incident_sla)
           })
         end
 

ee/spec/lib/ee/gitlab/usage_data_spec.rb

@@ -477,8 +477,7 @@ RSpec.describe Gitlab::UsageData do
         projects_incident_sla_enabled: 2
       )
       expect(described_class.usage_activity_by_stage_monitor(described_class.monthly_time_range_db_params)).to include(
-        operations_dashboard_users_with_projects_added: 1,
-        projects_incident_sla_enabled: 2
+        operations_dashboard_users_with_projects_added: 1
       )
     end
   end