[Add branch dialog] input scroll to remember entered value as one of items to scroll to

There's an option to scroll mouse wheel while [Branch:] input is focused. It will bring items from the dropdown one-by-one

The issue is that it replaces the entered value unrecoverably. Whatever you've written there will be lost and replaced with dropdown item you've scrolled to. For me it is usually an unintended action while pressing the [Add Branch & Checkout] button: I can accidentially trigger mosue wheel and it will do what I didn't want.

Solution: we may cache current value as one of the dropdown items, so when yopu scroll back it is reverted to whatever has been input there (the edited/new value). Thus we'll get an option to have what we had and use the scroll feature.