Remove obsolete alerts service helper

app/models/project.rb

@@ -2430,10 +2430,6 @@ class Project < ApplicationRecord
     protected_branches.limit(limit)
   end
 
-  def alerts_service_activated?
-    alerts_service&.active?
-  end
-
   def self_monitoring?
     Gitlab::CurrentSettings.self_monitoring_project_id == id
   end

spec/models/project_spec.rb

@@ -6275,28 +6275,6 @@ RSpec.describe Project, factory_default: :keep do
     end
   end
 
-  describe '#alerts_service_activated?' do
-    let!(:project) { create(:project) }
-
-    subject { project.alerts_service_activated? }
-
-    context 'when project has an activated alerts service' do
-      before do
-        create(:alerts_service, project: project)
-      end
-
-      it { is_expected.to be_truthy }
-    end
-
-    context 'when project has an inactive alerts service' do
-      before do
-        create(:alerts_service, :inactive, project: project)
-      end
-
-      it { is_expected.to be_falsey }
-    end
-  end
-
   describe '#prometheus_service_active?' do
     let(:project) { create(:project) }