[Select Tool] Clicking with the select tool when zoomed in selects an area of 0 pixels

Description When you click a 0x0 area, it should remove the current selection. If you're zoomed in, a 0x0 selection is created instead.

To Reproduce

1. Open Pinta
2. Activate the Selection tool
3. Zoom in such that an image pixel occupies more than 1 screen-space pixel
4. Click on the canvas

Additional Info

https://github.com/user-attachments/assets/4acf79d0-032f-4eb8-a471-c3c9c99f2e49

Version Latest git