improve _open_dataset_with_fallback to preserve original error behavior

Author: rajeeja

uxarray/core/utils.py

@@ -31,11 +31,17 @@ def _open_dataset_with_fallback(filename_or_obj, chunks=None, **kwargs):
     try:
         # Try opening with xarray's default read engine
         return xr.open_dataset(filename_or_obj, chunks=chunks, **kwargs)
-    except Exception:
-        # If it fails, use the "netcdf4" engine as backup
+    except Exception as first_error:
+        # If it fails, try with the "netcdf4" engine as backup
         # Extract engine from kwargs to prevent duplicate parameter error
         engine = kwargs.pop("engine", "netcdf4")
-        return xr.open_dataset(filename_or_obj, engine=engine, chunks=chunks, **kwargs)
+        try:
+            return xr.open_dataset(
+                filename_or_obj, engine=engine, chunks=chunks, **kwargs
+            )
+        except Exception:
+            # If both attempts fail, raise the original error to preserve the original behavior
+            raise first_error
 
 
 def _map_dims_to_ugrid(