Update profile informations as non-admin

On ETIP, non-admin users can change their password, but not the following fields:

- `Username`
- `First name`
- `Last name`
- `Email address`

Maybe we can create a profile page to update this informations?

The issue names a profile page and the Username, First name, Last name, and Email address fields, but no files or tests. Start by locating the existing non-admin password-change flow and the user account update entry point, then confirm the permission rules and validation. Done means non-admin users can update those fields while password changes continue to work.

Written by the indexing model from the issue text.