[UI] Pointer location icon changes position when moving cursor

[pedropaulosuzuki]

The pointer icon changes position as the pointer moves. Ideally the coordinates pair container should have a fixed width and the icon should be positioned on the left of the container, not changing in position.

https://github.com/user-attachments/assets/ad9d6e07-36cd-4a2e-8c87-399a47622429

Looks specially bad when the window is small and the color palette gets cut.

https://github.com/user-attachments/assets/8e0c93cd-d01f-42eb-af5f-c6faca6cbb33

[pedropaulosuzuki]

Same applies to selection size indicator.

https://github.com/user-attachments/assets/bb4b40ee-626a-4dfb-a4a5-ee13290b1480

[cameronwhite]

yeah, it probably should have enough space allocated for 5 digits, e.g. 10000 x 10000 to be safe

[ericksson]

I opened https://github.com/PintaProject/Pinta/pull/1540 with a proposed fix.