RSpec: Remove extra definitions not_change matcher

These definitions are redundant because the RSpec matcher has already
been created in spec/support/matchers/not_changed_matcher.rb.

ee/spec/requests/api/epics_spec.rb

@@ -41,8 +41,6 @@ describe API::Epics do
     let(:extra_date_fields) { %w[start_date_is_fixed start_date_fixed due_date_is_fixed due_date_fixed] }
 
     context 'when permission is absent' do
-      RSpec::Matchers.define_negated_matcher :exclude, :include
-
       it 'returns epic with extra date fields' do
         get api(url, user), params: params
 

ee/spec/requests/api/merge_request_approvals_spec.rb

@@ -301,8 +301,6 @@ describe API::MergeRequestApprovals do
   end
 
   describe 'PUT :id/merge_requests/:merge_request_iid/approvers' do
-    RSpec::Matchers.define_negated_matcher :not_change, :change
-
     shared_examples_for 'user allowed to change approvers' do
       context 'when disable_overriding_approvers_per_merge_request is true on the project' do
         before do

ee/spec/services/feature_flags/update_service_spec.rb

@@ -170,8 +170,6 @@ describe FeatureFlags::UpdateService do
       end
 
       context 'when scope can not be deleted' do
-        RSpec::Matchers.define_negated_matcher :not_change, :change
-
         before do
           allow(deleted_scope).to receive(:destroy).and_return(false)
         end

spec/requests/api/markdown_spec.rb

@@ -3,8 +3,6 @@
 require "spec_helper"
 
 describe API::Markdown do
-  RSpec::Matchers.define_negated_matcher :exclude, :include
-
   describe "POST /markdown" do
     let(:user) {} # No-op. It gets overwritten in the contexts below.
 

spec/services/x509_certificate_revoke_service_spec.rb

@@ -24,8 +24,6 @@ describe X509CertificateRevokeService do
     end
 
     context 'for good certificates' do
-      RSpec::Matchers.define_negated_matcher :not_change, :change
-
       let(:x509_certificate) { create(:x509_certificate) }
 
       it 'do not update any commit signature' do

spec/support/matchers/exclude_matcher.rb

+# frozen_string_literal: true
+
+RSpec::Matchers.define_negated_matcher :exclude, :include