bug(gui): torque map graph editing point collision detection broken

[t-bre]

Description

When dragging a point on the torque map, if the moving point crosses the x-coordinate of a different point, that other point will jump to the position of the moving point.

This is probably an issue with the collision detection between the mouse drag event position and the points on the graph.

Steps To Reproduce

1. Create some points on the torque map.
2. Drag one point so that it crosses the x-coordinate of another point.
3. The other point will jump to the position of the mouse cursor.

Environment

os       :  macOS 12.5.1
compiler :  clang++ v14.0.0

Expected Behaviour

Editing one point doesn't cause another point to move!

Additional Information

[t-bre]

This is part of the cause of #94