Fix deprecation of setting shape on a numpy array in 2.5+ (#3648)

* fix deprecation

* add changelog entry

Author: mscheltienne

changes/3648.misc.md

@@ -0,0 +1 @@
+Fix deprecation of setting a shape on an array directly in ``numpy`` 2.5+.

src/zarr/codecs/vlen_utf8.py

@@ -50,7 +50,7 @@ async def _decode_single(
         raw_bytes = chunk_bytes.as_array_like()
         decoded = _vlen_utf8_codec.decode(raw_bytes)
         assert decoded.dtype == np.object_
-        decoded.shape = chunk_spec.shape
+        decoded = decoded.reshape(chunk_spec.shape)
         as_string_dtype = decoded.astype(chunk_spec.dtype.to_native_dtype(), copy=False)
         return chunk_spec.prototype.nd_buffer.from_numpy_array(as_string_dtype)
 
@@ -95,7 +95,7 @@ async def _decode_single(
         raw_bytes = chunk_bytes.as_array_like()
         decoded = _vlen_bytes_codec.decode(raw_bytes)
         assert decoded.dtype == np.object_
-        decoded.shape = chunk_spec.shape
+        decoded = decoded.reshape(chunk_spec.shape)
         return chunk_spec.prototype.nd_buffer.from_numpy_array(decoded)
 
     async def _encode_single(