Two fixes to calculator widget

[Despacito696969]

1. Fixed mouse position being multiplied by two when using calculator widget.
2. Fixed incorrect behavior in client mode, where instead of creating a widget if a player has enabled the option, it would create as many widgets as the number of calculators player had. This meant that without a calculator you couldn't see the widget and with multiple calculators, every time you would open an inventory you would get multiple widgets spawned in the same place.

[Towdium]

Thanks！