text: Title: rebin for lazy signals change original signal chunks
  Body: When using `s.rebin` for lazy signals, the chunking of the original signal is changed. Tested in `RELEASE_next_minor`.
  
  Example:
  ```python
  import dask.array as da
  import hyperspy.api as hs
  s = hs.signals.Signal2D(da.zeros((256, 256, 256, 256))).as_lazy()
  print(s.data.chunksize) # (64, 64, 64, 64)
  s1 = s.rebin(scale=(2, 2, 2, 2))
  print(s.data.chunksize) # (256, 32, 32, 32)
  ```
  
  The original signal should not be changed with this type of operation.
  
  A workaround for this is using `rechunk=False`.