AO3-5610 notify users when a bookmark or series they have created is hidden #4567

Job	Run time
rake db:otwseed	1m 8s
rspec spec/controllers	11m 4s
rspec spec/models	5m 32s
rspec --exclude-pattern 'spec/{controllers,models}/*/.rb'	8m 35s
cucumber features/admins	5m 59s
cucumber features/bookmarks	4m 59s
cucumber features/collections	6m 12s
cucumber features/comments_and_kudos	6m 26s
cucumber features/gift_exchanges	6m 28s
cucumber features/importing	3m 4s
cucumber features/other_a	10m 5s
cucumber features/other_b	6m 17s
cucumber features/prompt_memes_a	3m 57s
cucumber features/prompt_memes_b	3m 30s
cucumber features/prompt_memes_c	4m 58s
cucumber features/search	6m 20s
cucumber features/tag_sets	3m 8s
cucumber features/tags_and_wrangling	6m 16s
cucumber features/users	4m 50s
cucumber features/works	13m 2s
	2h 1m 50s

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