Password field can't be empty message

[ChrisEdS]

Steps to reproduce

1. Create a public link
2. Add a password
3. Type in a password

Expected behaviour

Password field can't be empty message disappears when a password is set (when I start typing a password)

Actual behaviour

Password field can't be empty stays forever

[kulmann]

In order to make this issue actionable:

• for consistency with all other modals we should not show the empty password warning/error initially when the modal opens.
• the error message should be red (= error message style)
• like stated in the issue description the error message should go away as soon as the input fields holds at least one character