make zdtype abstract methods raise notimplementederror

[d-v-b]

[Description of PR]

TODO:

• Add unit tests and/or doctests in docstrings
• Add docstrings and API docs for any new/modified user-facing classes and functions
• New/modified features documented in docs/user-guide/*.rst
• Changes documented as a new file in changes/
• GitHub Actions have all passed
• Test coverage is 100% (Codecov passes)

[d-v-b]

partially addresses #3247

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 94.62%. Comparing base (18f41d4) to head (f7978d9).
⚠️ Report is 99 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3251   +/-   ##
=======================================
  Coverage   94.62%   94.62%           
=======================================
  Files          78       78           
  Lines        8690     8696    +6     
=======================================
+ Hits         8223     8229    +6     
  Misses        467      467           

Files with missing lines	Coverage Δ
src/zarr/core/dtype/wrapper.py	97.87% <100.00%> (+0.31%)	⬆️

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[dstansby]

I think you missed a couple of methods, specifically _from_json_v2 and _from_json_v3

[d-v-b]

I think you missed a couple of methods, specifically _from_json_v2 and _from_json_v3

good catch, I added these in f7978d9