cal.com fix: incorrect encryption string instructions

What does this PR do?

As outlined in https://github.com/calcom/cal.com/issues/13290, any new calcom user following the .env example is unable to perform any administrative function as 2FA is required.

Because "latin1" is specified as the encryption/decryption method in lib/crypto.ts, using a base64 encoded string (as is currently suggested) results in a 44 length string, which breaks the 2FA process.

A cleaner solution would be to update crypto.ts directly, but this was already rejected in https://github.com/calcom/cal.com/pull/13484 in favour of the ongoing refactor in https://github.com/calcom/cal.com/pull/12698. This PR is a temporary fix until the larger refactor has been completed.

Fixes #13290
Fixes CAL-3060

Mandatory Tasks

[x] I have self-reviewed the code (A decent size PR without self-review might be rejected)
[x] I have added a Docs issue here if this PR makes changes that would require a documentation change
[x] I have added or modified automated tests that prove my fix is effective or that my feature works (PRs might be rejected if logical changes are not properly tested)