feat(rust, python): Support reading UInt8, UInt16, Int8 and Int16 in newline delimited JSON

[krishanjmistry]

Implements #16167

Currently, attempting to use the read_ndjson function with a schema that specifies these types triggers the panic:

polars/crates/polars-io/src/ndjson/buffer.rs

Line 124 in acb601d

_ => panic!("unexpected dtype when deserializing ndjson"),

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 81.03%. Comparing base (acb601d) to head (df4776e).
Report is 27 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #16105      +/-   ##
==========================================
+ Coverage   80.97%   81.03%   +0.05%     
==========================================
  Files        1386     1387       +1     
  Lines      178479   178834     +355     
  Branches     2877     2882       +5     
==========================================
+ Hits       144530   144924     +394     
+ Misses      33458    33419      -39     
  Partials      491      491              

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