`<input>` unnecessarily increases Multiselect width

In the project I'm working on we have a few places where only 1 selection is to be made (`maxSelect` is 1). After making the selection the `<input>` unnecessarily takes up space, which makes CSS work harder when trying to fit everything, so I'm proposing that it is omitted in that case. I'm creating a PR for this (yay, my first code contribution to an open source project ever!).