Add Creator Sentiment Email task (#38787)

* Add new email function and send email to creator

* remove debug stuff

* add tests, address comments

* actually add tests

* Update src/metabase/email/messages.clj

Co-authored-by: Noah Moss <32746338+noahmoss@users.noreply.github.com>

* address comments

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Co-authored-by: Noah Moss <32746338+noahmoss@users.noreply.github.com>