inputmethod: hide virtual keyboard when not used with touch

Without this, the user needs to first focus a different surface or otherwise cancel the text input in order to hide the virtual keyboard. It's pretty annoying when I accidentally use the touch screen with maliit enabled to select something, when wanting to type with the physical keyboard.

Also contains some fixes for the slide effect showing an animation for the already hidden virtual keyboard, as well as Workspace wrongly showing the virtual keyboard in Workspace::updateToolWindows