message: fix(core): check if `prevClosestHandle` exists in `onPointerUp`
diff: @@ -154,9 +154,11 @@ export function handlePointerDown({
  }
  function onPointerUp(event: MouseEvent | TouchEvent) {
  + if (prevClosestHandle) {
  if (connection && isValid) {
  onConnect?.(connection);
  }
  + }
  // it's important to get a fresh reference from the store here
  // in order to get the latest state of onConnectEnd
  