Fix the distance for grabbing a EditorSpinSlider

[Sauermann]

Currently moving the mouse for a single pixel is enough to trigger grabbing, which happens often unintentionally.

resolve #78315
followup to #50671 which increased the change per pixel-move, but didn't adjust the minimal distance.

[akien-mga]

Likely a regression from #50671, CC @winston-yallow.

It added a multiplication by grabbing_spinner_speed in grabbing_spinner_dist_cache, which explains why the same needs to be done on the right hand side now. Might be worth checking if there are more uses of grabbing_spinner_dist_cache that need the same treatment, and whether that speed should have been multiplied there in the first place.

[Sauermann]

Might be worth checking if there are more uses of grabbing_spinner_dist_cache that need the same treatment

I did investigate this question, but didn't find any obvious place, where the same treatment was required.

[akien-mga]

Ah yes I just see in your OP that you actually linked to that PR already, my bad :)

[akien-mga]

Thanks!