Update 8_monitor tests to use outer describe

Remove monkey-patch for RSpec

qa/qa/specs/features/browser_ui/8_monitor/all_monitor_core_features_spec.rb

 # frozen_string_literal: true
 
 module QA
-  context 'Monitor' do
+  RSpec.describe 'Monitor' do
     describe 'with Prometheus in a Gitlab-managed cluster', :orchestrated, :kubernetes do
       before :all do
         @cluster = Service::KubernetesCluster.new.create!

qa/qa/specs/features/ee/browser_ui/8_monitor/all_monitor_features_spec.rb

@@ -2,7 +2,7 @@
 require 'pathname'
 
 module QA
-  context 'Monitor' do
+  RSpec.describe 'Monitor' do
     describe 'with Prometheus in a Gitlab-managed cluster', :orchestrated, :kubernetes do
       before :all do
         @cluster = Service::KubernetesCluster.new.create!