cleanup: remove unused generic drag threshold import

src/app/update/viewport.rs

@@ -8,7 +8,7 @@ use crate::app::helpers::{
     polar_constrain_if_near, polar_constrain_near, ucs_rotate_vec, ucs_to_wcs, ucs_z_axis,
     CoordKind,
 };
-use crate::app::{Message, OpenCADStudio, DRAG_START_FAST_PX2, POLY_START_DELAY_MS};
+use crate::app::{Message, OpenCADStudio, POLY_START_DELAY_MS};
 use crate::modules::ModuleEvent;
 use crate::scene::model::object::GripApply;
 use crate::scene::pick::grip::{