Fix line widget translation interaction bug

When moving a line widget with one of its axes at 0, it can lead to matrix calculation inaccuracies. Theses inaccuracies result in a computed value close to zero (approximately on the order of 1e-16), but not precisely zero as it should be. This slight offset prevent some filters relying on an intersection between a line and a plane to works correctly.

Fix this bug in projecting the new point onto a plane that is defined by the camera's orientation axis and a reference point within that plane.