AO3-6483 Make old password changes deserializable #3148

Job	Run time
rake db:otwseed	2m 1s
rspec spec/controllers	18m 25s
rspec spec/models	6m 44s
rspec --exclude-pattern 'spec/{controllers,models}/*/.rb'	10m 20s
cucumber features/admins	7m 19s
cucumber features/bookmarks	5m 46s
cucumber features/collections	7m 8s
cucumber features/comments_and_kudos	6m 50s
cucumber features/gift_exchanges	9m 11s
cucumber features/importing	3m 29s
cucumber features/other_a	13m 47s
cucumber features/other_b	8m 56s
cucumber features/prompt_memes_a	5m 9s
cucumber features/prompt_memes_b	6m 3s
cucumber features/prompt_memes_c	6m 21s
cucumber features/search	8m 58s
cucumber features/tag_sets	4m 40s
cucumber features/tags_and_wrangling	7m 26s
cucumber features/users	7m 11s
cucumber features/works	15m 8s
	2h 40m 52s

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