Drawing sliders when using a touch device doesn't work as expected

[peppy]

RPReplay_Final1705169711.mov

[Susko3]

Placing any kind of object with touch is broken: for the initial click, it uses the old mouse position instead of the new touch/mouse position. With sliders, only the first control point is broken.

This is because the position of the placement is updated in Update(), which happens after input handling finalises or starts the placement.

out.mp4

[bdach]

see #19422 (comment) for update on this i guess