Enforce correct sequencing of codecs in codec chain.

[zoj613]

This ensures that creation of a codec chain fails if the sequencing of codecs in the list is not correct. That is if the sequencing is not exactly: arraytoarray list -> 1 array-to-bytes -> bytestobytes list. That is one must supply the codecs in the order in which they intend to apply the encode/decode sequence.

[codecov]

Codecov Report

Attention: Patch coverage is 91.30435% with 2 lines in your changes missing coverage. Please review.

Project coverage is 97.80%. Comparing base (d50b2db) to head (b0d0e38).
Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
zarr/src/codecs/codecs.ml	90.90%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #65      +/-   ##
==========================================
- Coverage   97.81%   97.80%   -0.02%     
==========================================
  Files          17       17              
  Lines        1282     1275       -7     
==========================================
- Hits         1254     1247       -7     
  Misses         28       28              

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