Merge branch 'rename-undefined-methods' into 'master'

Replace reject_blocked with reject_blocked! in skipped callbacks.

`reject_blocked!` was introduced in c9def945, I can't find any references to `reject_blocked` ever existing.

See merge request !5532

app/controllers/explore/application_controller.rb

 class Explore::ApplicationController < ApplicationController
-  skip_before_action :authenticate_user!, :reject_blocked
+  skip_before_action :authenticate_user!, :reject_blocked!
   layout 'explore'
 end

app/controllers/help_controller.rb

 class HelpController < ApplicationController
-  skip_before_action :authenticate_user!, :reject_blocked
+  skip_before_action :authenticate_user!, :reject_blocked!
   layout 'help'

app/controllers/search_controller.rb

 class SearchController < ApplicationController
-  skip_before_action :authenticate_user!, :reject_blocked
+  skip_before_action :authenticate_user!, :reject_blocked!
   include SearchHelper