Input: Label text not being displayed if a `placeholder` is set

If a placeholder text is defined for `input`-elements, the label itself wouldn't get displayed until the input is focused, compare to e.g. https://db-ui.github.io/core/patterns/elements-input/index.html

more information on the usability and expected contents for that attribute: https://developer.mozilla.org/en-US/docs/Web/CSS/::placeholder#usability