Touchscreen controls for picture-in-picture view

### Problem

Currently the Close and resize buttons on PiP windows are not pressable on a touchscreen, they only appear when the window is being dragged and disappear once you lift your finger

### Proposal

1. Have the PiP window retain focus after being dragged with a touchscreen, so that the close and resize buttons are visible until another window is tapped on
2. Add a pinch gesture to resize a PiP window with two fingers

### Prior Art (Optional)

_No response_