Port from 4.2 branch (PR #2996):
- Fix dangling pointer in SpineSkeletonDataResource destructor by using
ObjectID validation instead of direct EditorFileSystem access
- Register format loaders/savers at CORE level for GDExtension to fix
loader/saver registration issues (#2899)
Additional fix for GDExtension:
- Fix crash on editor shutdown by properly removing import/inspector
plugins in NOTIFICATION_PREDELETE before the extension is unloaded