Fix missing spatial object when creating a new bounding box with enclosing_bbox

Author: Belval

textractor/entities/bbox.py

@@ -213,6 +213,9 @@ def enclosing_bbox(cls, bboxes, spatial_object: SpatialObject = None):
             logging.warning("At least one bounding box needs to be non-null")
             return BoundingBox(0, 0, 1, 1, spatial_object=spatial_object)            
 
+        if spatial_object is None:
+            spatial_object = bboxes[0].spatial_object
+
         for bbox in bboxes:
             if bbox is not None:
                 x1 = min(x1, bbox.x)