AO3-6848 Create unique tags for mailer preview #4987

Job	Run time
rake db:otwseed	3m 11s
rspec spec/controllers	14m 47s
rspec spec/models	11m 41s
rspec --exclude-pattern 'spec/{controllers,models}/*/.rb'	9m 6s
cucumber features/admins	10m 2s
cucumber features/bookmarks	4m 36s
cucumber features/collections	10m 12s
cucumber features/comments_and_kudos	10m 27s
cucumber features/gift_exchanges	7m 23s
cucumber features/importing	3m 50s
cucumber features/other_a	11m 6s
cucumber features/other_b	6m 45s
cucumber features/prompt_memes_a	4m 14s
cucumber features/prompt_memes_b	9m 32s
cucumber features/prompt_memes_c	6m 1s
cucumber features/search	7m 22s
cucumber features/tag_sets	3m 17s
cucumber features/tags_and_wrangling	7m 19s
cucumber features/users	9m 32s
cucumber features/works	13m 4s
	2h 43m 27s

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