Include deployment_tier to pipeline environment hook attributes

We have a [customer request](https://gitlab.com/gitlab-org/gitlab/-/issues/335558) to include `deployment_tier` to the pipeline webhook event payload. In this [MR](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/66744) we are making changes for the same.

Changelog: changed
MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/66744

doc/user/project/integrations/webhooks.md

@@ -1157,7 +1157,8 @@ X-Gitlab-Event: Pipeline Hook
          },
          "environment": {
            "name": "production",
-           "action": "start"
+           "action": "start",
+           "deployment_tier": "production"
          }
       },
       {
@@ -1291,7 +1292,8 @@ X-Gitlab-Event: Pipeline Hook
          },
          "environment": {
            "name": "staging",
-           "action": "start"
+           "action": "start",
+           "deployment_tier": "staging"
          }
       }
    ]

lib/gitlab/data_builder/pipeline.rb

@@ -91,7 +91,8 @@ module Gitlab
 
         {
           name: build.expanded_environment_name,
-          action: build.environment_action
+          action: build.environment_action,
+          deployment_tier: build.persisted_environment.try(:tier)
         }
       end
     end

spec/factories/ci/builds.rb

@@ -120,6 +120,19 @@ FactoryBot.define do
       end
     end
 
+    trait :environment_with_deployment_tier do
+      environment { 'test_portal' }
+      options do
+        {
+          script: %w(ls),
+          environment: { name: 'test_portal',
+            action: 'start',
+            url: 'http://staging.example.com/$CI_JOB_NAME',
+            deployment_tier: 'testing' }
+        }
+      end
+    end
+
     trait :deploy_to_production do
       environment { 'production' }
 

spec/lib/gitlab/data_builder/pipeline_spec.rb

@@ -119,10 +119,14 @@ RSpec.describe Gitlab::DataBuilder::Pipeline do
     end
 
     context 'build with environment' do
-      let!(:build) { create(:ci_build, :teardown_environment, pipeline: pipeline) }
+      let!(:build) { create(:ci_build, :environment_with_deployment_tier, :with_deployment, pipeline: pipeline) }
+      let!(:build_environment_data) { build_data[:environment] }
 
-      it { expect(build_data[:environment][:name]).to eq(build.expanded_environment_name) }
-      it { expect(build_data[:environment][:action]).to eq(build.environment_action) }
+      it 'has environment attributes', :aggregate_failures do
+        expect(build_environment_data[:name]).to eq(build.expanded_environment_name)
+        expect(build_environment_data[:action]).to eq(build.environment_action)
+        expect(build_environment_data[:deployment_tier]).to eq(build.persisted_environment.try(:tier))
+      end
     end
   end
 end