QSelect: Option to clear input text on select

[adam-earthscope]

This is a feature that has been suggested before (#4732, #4600, #5038, #5041) but it's been several years and I would like this to be reconsidered.

When a QSelect uses multiple and use-input (and possibly in other cases), when the user selects an option the existing input text remains in the widget.

Codepen example: https://codepen.io/adam-earthscope/pen/ogxmqLW

I understand the reason for this behavior, but there are also cases where this isn't wanted. I'd like to propose a new QSelect attribute that would clear the input text on selection. The Vuetify equivalent is clear-on-select which seems intuitive to me.