Go to you admin page, on the left choose security, then you should be able to modify the password policy settings. If you want to disable it completely, go to the apps page, and disable the app Password Policy.
So the conclusion is that the password policy found under Security -> Password policy controls both the user password and the shared link password policy.
As stated by the github link, Currently the app checks passwords for public link shares and for user passwords if the database backend is used.
This means that the current documentation is outdated since the screenshot and app Share Link Password Policy does no longer exist? And of course theres no way to control them independently of each other?
Edit: This also means theres no way to specify the “Link expiration” settings as specified in the documentation?