Fix: Ensure coord_path is a string in DirectSelect.onVertex

[BlockCnFuture]

Problem

DirectSelect.onVertex fails when dragging MultiPoint geometries due to the coord_path property not being consistently a string. This causes issues, especially when dragging vertices in MultiPoint geometries.

Solution

• Added a type check and conversion for coord_path to ensure it is always treated as a string:

  if (typeof about.coord_path !== 'string') about.coord_path = String(about.coord_path);