Fix flay not detecting identical code

Previously the script checked only for 'Similar code', but flay will
tell users when IDENTICAL code is detected too. This should create a
commit will create a failing pipeline, and to check that it does this
commit is pushed.

Fixes #42628

lib/tasks/flay.rake

@@ -2,7 +2,7 @@ desc 'Code duplication analyze via flay'
 task :flay do
   output = `bundle exec flay --mass 35 app/ lib/gitlab/ 2> #{File::NULL}`
 
-  if output.include? "Similar code found"
+  if output.include?("Similar code found") || output.include?("IDENTICAL code found")
     puts output
     exit 1
   end