Remove deprecation_message from service

- deprecation_message is nil by default and no child
classes are overwriting the value, thus it is always nil
- Views are now redundant since they won't render

app/models/service.rb

@@ -349,10 +349,6 @@ class Service < ApplicationRecord
     false
   end
 
-  def deprecation_message
-    nil
-  end
-
   # override if needed
   def supports_data_fields?
     false

app/views/admin/services/_deprecated_message.html.haml

-.flash-container.flash-container-page
-  .flash-alert.deprecated-service
-    %span= @service.deprecation_message

app/views/admin/services/edit.html.haml

@@ -2,6 +2,4 @@
 - breadcrumb_title @service.title
 - page_title @service.title, "Service Templates"
 
-= render 'deprecated_message' if @service.deprecation_message
-
 = render 'form'

app/views/projects/services/_deprecated_message.html.haml

-.flash-container.flash-container-page
-  .flash-alert.deprecated-service
-    %span= @service.deprecation_message

app/views/projects/services/edit.html.haml

@@ -2,8 +2,6 @@
 - add_to_breadcrumbs _('Integration Settings'), project_settings_integrations_path(@project)
 - page_title @service.title, _('Integrations')
 
-= render 'deprecated_message' if @service.deprecation_message
-
 = render 'form'
 - if @web_hook_logs
   = render partial: 'projects/hook_logs/index', locals: { hook: @service.service_hook, hook_logs: @web_hook_logs, project: @project }

spec/fixtures/trace/sample_trace

@@ -2770,8 +2770,6 @@ Service
       updates the has_external_issue_tracker boolean
   #deprecated?
     should return false by default
-  #deprecation_message
-    should be empty by default
   #api_field_names
     filters out sensitive fields
 

spec/models/service_spec.rb

@@ -532,15 +532,6 @@ describe Service do
     end
   end
 
-  describe "#deprecation_message" do
-    let(:project) { create(:project, :repository) }
-
-    it 'is empty by default' do
-      service = create(:service, project: project)
-      expect(service.deprecation_message).to be_nil
-    end
-  end
-
   describe '#api_field_names' do
     let(:fake_service) do
       Class.new(Service) do