fix: Arrow drag start in bindable area jumps across bindable (#10676)

Signed-off-by: Mark Tolmacs <mark@lazycat.hu>

packages/element/src/binding.ts

@@ -15,6 +15,7 @@ import {
   pointFrom,
   pointFromVector,
   pointRotateRads,
+  pointsEqual,
   vectorFromPoint,
   vectorNormalize,
   vectorScale,
@@ -1602,7 +1603,12 @@ export const updateBoundPoint = (
   if (
     binding == null ||
     // We only need to update the other end if this is a 2 point line element
-    (binding.elementId !== bindableElement.id && arrow.points.length > 2)
+    (binding.elementId !== bindableElement.id && arrow.points.length > 2) ||
+    // Initial arrow created on pointer down needs to not update the points
+    pointsEqual(
+      arrow.points[arrow.points.length - 1],
+      pointFrom<LocalPoint>(0, 0),
+    )
   ) {
     return null;
   }