Improves the expect_next spec implementation

ee/spec/features/registrations/saas_user_registration_spec.rb

@@ -3,6 +3,8 @@
 require 'spec_helper'
 
 RSpec.describe "User registration", :js, :saas do
+  include AfterNextHelpers
+
   let_it_be(:user) { create(:user) }
 
   before do
@@ -155,8 +157,7 @@ RSpec.describe "User registration", :js, :saas do
           before do
             click_button class: 'gl-toggle'
 
-            expect_next_instance_of(GitlabSubscriptions::CreateLeadService) do |service|
-              expect(service).to receive(:execute).with(
+            expect_next(GitlabSubscriptions::CreateLeadService).to receive(:execute).with(
               trial_user: ActionController::Parameters.new(
                 company_name: '',
                 company_size: '',
@@ -172,7 +173,6 @@ RSpec.describe "User registration", :js, :saas do
                 newsletter_segment: true
               ).permit!
             ).and_return(success: true)
-            end
 
             click_on 'Continue'
           end
@@ -183,8 +183,7 @@ RSpec.describe "User registration", :js, :saas do
             fill_in 'group_name', with: 'Test Group'
             fill_in 'blank_project_name', with: 'Test Project'
 
-            expect_next_instance_of(GitlabSubscriptions::CreateLeadService) do |service|
-              expect(service).to receive(:execute).with(
+            expect_next(GitlabSubscriptions::CreateLeadService).to receive(:execute).with(
               uid: user.id,
               trial_user:
                 ActionController::Parameters.new(
@@ -194,7 +193,6 @@ RSpec.describe "User registration", :js, :saas do
                   sync_to_gl: true
                 ).permit!
             ).and_return(success: true)
-            end
 
             click_on 'Create project'