Add number of approval project rules to usage ping

Adds usage ping for:

- Number of project approval rules
- Number of project approval rule with not default target branch

changelogs/unreleased/id-approval-rules-usage-ping.yml

+---
+title: Add number of approval project rules to usage ping
+merge_request: 36316
+author:
+type: added

doc/development/telemetry/usage_ping.md

@@ -662,6 +662,8 @@ appear to be associated to any of the services running, since they all appear to
 | `projects_with_repositories_enabled`                                | `usage_activity_by_stage`            | `create`      |                  | EE      |                                                                            |
 | `protected_branches`                                                | `usage_activity_by_stage`            | `create`      |                  | EE      |                                                                            |
 | `suggestions`                                                       | `usage_activity_by_stage`            | `create`      |                  | EE      |                                                                            |
+| `approval_project_rules`                                  | `usage_activity_by_stage`            | `create`      |                  | EE      | Number of project approval rules                                           |
+| `approval_project_rules_with_target_branch`               | `usage_activity_by_stage`            | `create`      |                  | EE      | Number of project approval rules with not default target branch            |
 | `clusters`                                                | `usage_activity_by_stage`            | `monitor`     |                  | CE+EE   |                                                                            |
 | `clusters_applications_prometheus`                        | `usage_activity_by_stage`            | `monitor`     |                  | CE+EE   |                                                                            |
 | `operations_dashboard_default_dashboard`                  | `usage_activity_by_stage`            | `monitor`     |                  | CE+EE   |                                                                            |

ee/app/models/approval_project_rules_protected_branch.rb

+# frozen_string_literal: true
+
+# Model for join table between ApprovalProjectRule and ProtectedBranch
+class ApprovalProjectRulesProtectedBranch < ApplicationRecord
+end

ee/lib/ee/gitlab/usage_data.rb

@@ -97,6 +97,13 @@ module EE
         end
 
         # rubocop: disable CodeReuse/ActiveRecord
+        def approval_rules_counts
+          {
+            approval_project_rules: count(ApprovalProjectRule),
+            approval_project_rules_with_target_branch: count(ApprovalProjectRulesProtectedBranch, :approval_project_rule_id)
+          }
+        end
+
         def service_desk_counts
           projects_with_service_desk = ::Project.where(service_desk_enabled: true)
 
@@ -223,7 +230,7 @@ module EE
                                         :author_id,
                                         start: user_minimum_id,
                                         finish: user_maximum_id)
-          })
+          }, approval_rules_counts)
         end
 
         # Omitted because no user, creator or author associated: `campaigns_imported_from_github`, `ldap_group_links`

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

@@ -301,7 +301,7 @@ RSpec.describe Gitlab::UsageData do
       end
 
       context 'for create' do
-        it 'includes accurate usage_activity_by_stage data' do
+        it 'includes accurate usage_activity_by_stage data', :aggregate_failures do
           for_defined_days_back do
             user = create(:user)
             project = create(:project, :repository_private, :github_imported,
@@ -310,7 +310,9 @@ RSpec.describe Gitlab::UsageData do
             create(:project, creator: user)
             create(:project, creator: user, disable_overriding_approvers_per_merge_request: true)
             create(:project, creator: user, disable_overriding_approvers_per_merge_request: false)
-            create(:protected_branch, project: project)
+            create(:approval_project_rule, project: project)
+            protected_branch = create(:protected_branch, project: project)
+            create(:approval_project_rule, protected_branches: [protected_branch], project: project)
             create(:suggestion, note: create(:note, project: project))
             create(:code_owner_rule, merge_request: merge_request, approvals_required: 3)
             create(:code_owner_rule, merge_request: merge_request, approvals_required: 7)
@@ -319,6 +321,8 @@ RSpec.describe Gitlab::UsageData do
           end
 
           expect(described_class.uncached_data[:usage_activity_by_stage][:create]).to include(
+            approval_project_rules: 4,
+            approval_project_rules_with_target_branch: 2,
             projects_enforcing_code_owner_approval: 0,
             merge_requests_with_optional_codeowners: 4,
             merge_requests_with_required_codeowners: 8,
@@ -328,6 +332,8 @@ RSpec.describe Gitlab::UsageData do
             suggestions: 2
           )
           expect(described_class.uncached_data[:usage_activity_by_stage_monthly][:create]).to include(
+            approval_project_rules: 4,
+            approval_project_rules_with_target_branch: 2,
             projects_enforcing_code_owner_approval: 0,
             merge_requests_with_optional_codeowners: 2,
             merge_requests_with_required_codeowners: 4,