Fix: allow "bytes" as an alias for "variable_length_bytes"

[d-v-b]

A simple change that treats "bytes" as an alias for "variable_length_bytes". This will address part of the problems revealed in #3513

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 61.86%. Comparing base (7fe95b5) to head (5d6b515).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3532   +/-   ##
=======================================
  Coverage   61.86%   61.86%           
=======================================
  Files          85       85           
  Lines       10112    10112           
=======================================
  Hits         6256     6256           
  Misses       3856     3856           

Files with missing lines	Coverage Δ
src/zarr/core/dtype/npy/bytes.py	53.00% <100.00%> (ø)

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[d-v-b]

@zarr-developers/python-core-devs could someone review this? It would be nice to have this merged today in time for a release.