[AlertDialog][ContextMenu][Dialog][DropdownMenu][Popover][Select] Remove allowPinchZoom prop

[benoitgrelard]

• allowPinchZoom was false by default, which is by default an accessibility issue.
• It also means if users want it back, it's impossible to bring back without the extra prop
• after experimenting with our own remove scroll ideas during hack week, we concluded pinch zooming should be allowed by default and that if users want to disallow that, they can do it themselves, so we're removing the prop and hardcoding to true for now so we don't create an extra breaking change for it after v1.