Add reliable tag to related issues and scoped labels e2e tests

qa/qa/specs/features/browser_ui/2_plan/related_issues/related_issues_spec.rb

 # frozen_string_literal: true
 
 module QA
-  RSpec.describe 'Plan' do
+  RSpec.describe 'Plan', :reliable do
     describe 'Related issues' do
       let(:project) do
         Resource::Project.fabricate_via_api! do |project|

qa/qa/specs/features/ee/browser_ui/2_plan/scoped_labels/editing_scoped_labels_spec.rb

 # frozen_string_literal: true
 
 module QA
-  RSpec.describe 'Plan' do
+  RSpec.describe 'Plan', :reliable do
     describe 'Editing scoped labels on issues' do
       let(:initial_label) { 'animal::fox' }
       let(:new_label_same_scope) { 'animal::dolphin' }