New cursor doesn't match precise location picker (on mobile)

[thibaultmol]

I think in the code there might be a mismatch between the viewport resolution and screen resolution. So (only on mobile) if you put the cursor at a clearly defined location and then try to create a new object, you'll see the location picker is slightly lower (because it's using the viewport resolution, which has a lower height. So doing that /2 will give a lower value.)