Store slice instead of range in ZSlice

[wyfo]

Dynamic dispatch of ZSliceBuffer::as_slice was hurting deserialization performance.

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Labels: internal

🏠 Internal Change

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[codecov]

Codecov Report

❌ Patch coverage is 95.65217% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 71.96%. Comparing base (3c77c34) to head (dfc3e3e).

Files with missing lines	Patch %	Lines
commons/zenoh-buffers/src/zslice.rs	95.38%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2379      +/-   ##
==========================================
+ Coverage   71.91%   71.96%   +0.04%     
==========================================
  Files         390      390              
  Lines       62764    62810      +46     
==========================================
+ Hits        45139    45203      +64     
+ Misses      17625    17607      -18     

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