fix dtype mechanics in bytescodec

Author: d-v-b

src/zarr/codecs/bytes.py

@@ -71,14 +71,8 @@ async def _decode_single(
         chunk_spec: ArraySpec,
     ) -> NDBuffer:
         assert isinstance(chunk_bytes, Buffer)
-        if chunk_spec.dtype.unwrap().itemsize > 0:
-            if self.endian == Endian.little:
-                prefix = "<"
-            else:
-                prefix = ">"
-            dtype = np.dtype(f"{prefix}{chunk_spec.dtype.unwrap().str[1:]}")
-        else:
-            dtype = np.dtype(f"|{chunk_spec.dtype.unwrap().str[1:]}")
+
+        dtype = chunk_spec.dtype.with_endianness(self.endian).unwrap()
 
         as_array_like = chunk_bytes.as_array_like()
         if isinstance(as_array_like, NDArrayLike):