Fix incorrect message after resetting password

Problem/Motivation

After a user has reset their password, they are shown a message:

You have just used your one-time login link. It is no longer necessary to use this link to log in. Please change your password.

As it's a one-time login link, it's not possible to use it again to log in rather than "necessary" which the message currently says.

This patch corrects the message.

Steps to reproduce

Proposed resolution

"You have logged in with your one-time login link. Set your new password now, it is not possible to use this link a second time."

See UX review in #37

Remaining tasks

1. Update for changes from #2921133: Remove "Please" from the codebase.

User interface changes

Before

After

API changes

Data model changes

Release notes snippet