Remove legacy attribute and session encryptor

[jmhooper]

Why: We have moved all of the attributes away from the old attribute
encryption method and we have definitely dropped all of the sessions
that were encrypted with the old encryptor.

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[stevegsa]

Nice catch!

[stevegsa]

LGTM. Did we run the bulk migration in prod?

[jmhooper]

Yep, there shouldn't be any more legacy ciphertexts in dev, int, staging, or prod.

[ayoubbakkar123]

[REDACTED]

Note: Comment edited by repository maintainers to remove sensitive content.