Draw.io defaults to 2.5 mm in Gird, but the value is actually not the grid value.

Preflight Checklist

• I agree to follow the Code of Conduct that this project adheres to.
• I have searched the issue tracker for a feature request that matches the one I want to file, without success.

Describe the bug When I set the Unit to mm the GUI shows a grid value of 2.5 mm. But, if I draw a rect, using the size of the react is e.g. 10.2 mm x 10.2 mm when the edges align to the grid (snapping to grid). If I go into the value editor and re-type 2.5 mm into the editor the grid is changed. From this on the snapped rects have the multiple of 2.5 mm in size, e.g. 10.0 mm x 10.0 mm

To Reproduce Steps to reproduce the behavior:

1. Start a new diagram
2. Switch unit to mm
3. Switch the grid to visible / active
4. Check that 2.5 mm is shown for the grid size (do not re-edit the value!!)
5. Try to draw a rect with size 10.0 mm x 10.0 mm (using snapping on the grid)
6. The tooltip in the corner of the rect shows the size 10.2 mm x 10.2 mm

Expected behavior 10.0 mm x 10.0 mm should be possible

Screenshots

draw.io version (In the Help->About menu of the draw.io editor):

• draw.io version 29.4.0 (Web Version)

Additional context Add any other context about the problem here.