Add ApprovalRulePresenter for private group filter

Similar to MergeRequestPresenter

ee/app/presenters/approval_rule_presenter.rb

+# frozen_string_literal: true
+
+class ApprovalRulePresenter < Gitlab::View::Presenter::Delegated
+  def groups
+    super.public_or_visible_to_user(current_user)
+  end
+end

ee/spec/presenters/approval_rule_presenter_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe ApprovalRulePresenter do
+  describe '#groups' do
+    set(:user) { create(:user) }
+    set(:public_group) { create(:group) }
+    set(:private_group) { create(:group, :private) }
+    let(:groups) { [public_group, private_group] }
+
+    shared_examples 'filtering private group' do
+      subject { described_class.new(rule, current_user: user) }
+
+      context 'when user has no access to private group' do
+        it 'excludes private group' do
+          expect(subject.groups).to contain_exactly(public_group)
+        end
+      end
+
+      context 'when user has access to private group' do
+        it 'includes private group' do
+          private_group.add_owner(user)
+
+          expect(subject.groups).to contain_exactly(*groups)
+        end
+      end
+    end
+
+    context 'project rule' do
+      let(:rule) { create(:approval_project_rule, groups: groups) }
+
+      it_behaves_like 'filtering private group'
+    end
+
+    context 'wrapped approval rule' do
+      let(:rule) do
+        mr_rule = create(:approval_merge_request_rule, groups: groups)
+        ApprovalWrappedRule.new(mr_rule.merge_request, mr_rule)
+      end
+
+      it_behaves_like 'filtering private group'
+    end
+  end
+end