Comment 6 for bug 1977554

Noting a couple points from https://technology.blog.gov.uk/2021/04/19/simple-things-are-complicated-making-a-show-password-option/

- Since a design point of the OPAC is that it should be able to perform all core functions without JavaScript enabled, we should consider hiding the checkbox by default and display it only if JS is available
- We should consider adding a form submit handler to change the type of the password input back to 'password' before submitting the login form as a way of avoiding the password ending up in the brower's autocomplete history.