Delegate `project_id` to `pipeline`

Instead of reading the attribute directly from pipeline, we should
delegate the `project_id` call to `pipeline`.

ee/app/finders/security/findings_finder.rb

@@ -111,7 +111,7 @@ module Security
 
     def all_security_findings
       pipeline.security_findings
-              .with_build_and_artifacts
+              .with_pipeline_entities
               .with_scan
               .with_scanner
               .deduplicated

ee/app/models/security/finding.rb

@@ -38,7 +38,7 @@ module Security
                 .where('vulnerability_feedback.project_fingerprint = security_findings.project_fingerprint'))
     end
     scope :ordered, -> { order(severity: :desc, confidence: :desc, id: :asc) }
-    scope :with_build_and_artifacts, -> { includes(build: [:job_artifacts, :pipeline]) }
+    scope :with_pipeline_entities, -> { includes(build: [:job_artifacts, pipeline: :project]) }
     scope :with_scan, -> { includes(:scan) }
     scope :with_scanner, -> { includes(:scanner) }
     scope :deduplicated, -> { where(deduplicated: true) }

ee/lib/gitlab/ci/reports/security/report.rb

@@ -8,6 +8,8 @@ module Gitlab
           attr_reader :created_at, :type, :pipeline, :findings, :scanners, :identifiers
           attr_accessor :scan, :scanned_resources, :error
 
+          delegate :project_id, to: :pipeline
+
           def initialize(type, pipeline, created_at)
             @type = type
             @pipeline = pipeline
@@ -55,15 +57,6 @@ module Gitlab
           def primary_scanner
             scanners.first&.second
           end
-
-          # It's important to read the `project_id` attribute instead of calling
-          # `project_id` on pipeline. Because the `Ci::Pipeline` delegates the `project_id`
-          # call to the `project` relation even though it already has the attribute called
-          # `project_id`. By reading attribute directly from the entity, we are preventing
-          # an extra database query to load the project.
-          def project_id
-            pipeline&.read_attribute(:project_id)
-          end
         end
       end
     end

ee/spec/finders/security/findings_finder_spec.rb

@@ -91,7 +91,7 @@ RSpec.describe Security::FindingsFinder do
         end
 
         it 'does not cause N+1 queries' do
-          expect { finder_result }.not_to exceed_query_limit(8)
+          expect { finder_result }.not_to exceed_query_limit(9)
         end
 
         describe '#current_page' do

ee/spec/lib/gitlab/ci/reports/security/report_spec.rb

@@ -6,9 +6,11 @@ RSpec.describe Gitlab::Ci::Reports::Security::Report do
   let_it_be(:pipeline) { create(:ci_pipeline) }
 
   let(:created_at) { 2.weeks.ago }
-  let(:report) { described_class.new('sast', pipeline, created_at) }
+
+  subject(:report) { described_class.new('sast', pipeline, created_at) }
 
   it { expect(report.type).to eq('sast') }
+  it { is_expected.to delegate_method(:project_id).to(:pipeline) }
 
   describe '#add_scanner' do
     let(:scanner) { create(:ci_reports_security_scanner, external_id: 'find_sec_bugs') }
@@ -137,10 +139,4 @@ RSpec.describe Gitlab::Ci::Reports::Security::Report do
 
     it { is_expected.to eq(scanner_1) }
   end
-
-  describe '#project_id' do
-    subject { report.project_id }
-
-    it { is_expected.to eq(pipeline.project_id) }
-  end
 end