Remove references to service from field entity spec

spec/serializers/service_field_entity_spec.rb

@@ -5,7 +5,7 @@ require 'spec_helper'
 RSpec.describe ServiceFieldEntity do
   let(:request) { double('request') }
 
-  subject { described_class.new(field, request: request, service: service).as_json }
+  subject { described_class.new(field, request: request, service: integration).as_json }
 
   before do
     allow(request).to receive(:service).and_return(integration)
@@ -16,7 +16,7 @@ RSpec.describe ServiceFieldEntity do
       let(:integration) { create(:jira_integration) }
 
       context 'field with type text' do
-        let(:field) { integration.global_fields.find { |field| field[:name] == 'username' } }
+        let(:field) { integration_field('username') }
 
         it 'exposes correct attributes' do
           expected_hash = {
@@ -35,7 +35,7 @@ RSpec.describe ServiceFieldEntity do
       end
 
       context 'field with type password' do
-        let(:field) { integration.global_fields.find { |field| field[:name] == 'password' } }
+        let(:field) { integration_field('password') }
 
         it 'exposes correct attributes but hides password' do
           expected_hash = {
@@ -56,10 +56,9 @@ RSpec.describe ServiceFieldEntity do
 
     context 'EmailsOnPush Service' do
       let(:integration) { create(:emails_on_push_integration, send_from_committer_email: '1') }
-      let(:service) { integration } # TODO: remove when https://gitlab.com/gitlab-org/gitlab/-/issues/330300 is complete
 
       context 'field with type checkbox' do
-        let(:field) { integration.global_fields.find { |field| field[:name] == 'send_from_committer_email' } }
+        let(:field) { integration_field('send_from_committer_email') }
 
         it 'exposes correct attributes and casts value to Boolean' do
           expected_hash = {
@@ -78,7 +77,7 @@ RSpec.describe ServiceFieldEntity do
       end
 
       context 'field with type select' do
-        let(:field) { integration.global_fields.find { |field| field[:name] == 'branches_to_be_notified' } }
+        let(:field) { integration_field('branches_to_be_notified') }
 
         it 'exposes correct attributes' do
           expected_hash = {
@@ -97,4 +96,8 @@ RSpec.describe ServiceFieldEntity do
       end
     end
   end
+
+  def integration_field(name)
+    integration.global_fields.find { |f| f[:name] == name }
+  end
 end