Make scroll sensitivity configurable + better touchpad support

[Fusion86]

ScrcpyNet/src/ScrcpyNet.Wpf/ScrcpyDisplay.cs

Line 163 in cfd1059

msg.VerticalScroll = e.Delta / 120; // Random guess

Maybe replace this with Math.Clamp(e.Delta, -1, 1);? Though this still results in a too high sensitivity on touchpads.

[quanstar]

If you can scroll once, you can't scroll anymore