Password validation inconsistent: minimum 6 or 8?

[mccalluc]

If a very short password is provided, the UI returns two different error messages in different places:

• Your password must be at least 6 characters long
• This password is too short. It must contain at least 8 characters

Rather than focusing on the discrepancy, I'd suggest clarifying which part of the code is responsible for input validation, and just remove the other part.

(I'm running the CI docker compose locally on a fresh checkout, if that makes a difference.)