Remove the unused suggestion usage data

This is currently covered by suggestion by
  i_code_review_user_add_suggestion in HLL

MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/77570
Issue: https://gitlab.com/gitlab-org/gitlab/-/issues/348408

config/metrics/counts_28d/20210216175109_suggestions.yml

@@ -8,7 +8,7 @@ product_stage: create
 product_group: group::code review
 product_category: code_review
 value_type: number
-status: active
+status: removed
 time_frame: 28d
 data_source: database
 distribution:
@@ -20,3 +20,4 @@ tier:
 - ultimate
 performance_indicator_type: []
 milestone: "<13.9"
+milestone_removed: '14.7'

config/metrics/counts_all/20210216175053_suggestions.yml

@@ -7,7 +7,7 @@ product_stage: create
 product_group: group::code review
 product_category: code_review
 value_type: number
-status: active
+status: removed
 time_frame: all
 data_source: database
 distribution:
@@ -18,3 +18,4 @@ tier:
 - premium
 - ultimate
 milestone: "<13.9"
+milestone_removed: '14.7'

lib/gitlab/usage_data.rb

@@ -522,11 +522,7 @@ module Gitlab
           projects_with_disable_overriding_approvers_per_merge_request: count(::Project.where(time_period.merge(disable_overriding_approvers_per_merge_request: true))),
           projects_without_disable_overriding_approvers_per_merge_request: count(::Project.where(time_period.merge(disable_overriding_approvers_per_merge_request: [false, nil]))),
           remote_mirrors: distinct_count(::Project.with_remote_mirrors.where(time_period), :creator_id),
-          snippets: distinct_count(::Snippet.where(time_period), :author_id),
-          suggestions: distinct_count(::Note.with_suggestions.where(time_period),
-                                      :author_id,
-                                      start: minimum_id(::User),
-                                      finish: maximum_id(::User))
+          snippets: distinct_count(::Snippet.where(time_period), :author_id)
         }.tap do |h|
           if time_period.present?
             h[:merge_requests_users] = merge_requests_users(time_period)

spec/lib/gitlab/usage_data_spec.rb

@@ -161,7 +161,6 @@ RSpec.describe Gitlab::UsageData, :aggregate_failures do
         another_project = create(:project, :repository, creator: another_user)
         create(:remote_mirror, project: another_project, enabled: false)
         create(:snippet, author: user)
-        create(:suggestion, note: create(:note, project: project))
       end
 
       expect(described_class.usage_activity_by_stage_create({})).to include(
@@ -171,8 +170,7 @@ RSpec.describe Gitlab::UsageData, :aggregate_failures do
         projects_with_disable_overriding_approvers_per_merge_request: 2,
         projects_without_disable_overriding_approvers_per_merge_request: 6,
         remote_mirrors: 2,
-        snippets: 2,
-        suggestions: 2
+        snippets: 2
       )
       expect(described_class.usage_activity_by_stage_create(described_class.monthly_time_range_db_params)).to include(
         deploy_keys: 1,
@@ -181,8 +179,7 @@ RSpec.describe Gitlab::UsageData, :aggregate_failures do
         projects_with_disable_overriding_approvers_per_merge_request: 1,
         projects_without_disable_overriding_approvers_per_merge_request: 3,
         remote_mirrors: 1,
-        snippets: 1,
-        suggestions: 1
+        snippets: 1
       )
     end
   end