fix: Ensure out-of-range integers and other edge case values don't give wrong results for index_of()

[itamarst]

Fixes #23476

Previously out-of-range integers would be cast to Null, and then if there was a Null in the series its index would be returned. I.e. index_of() was giving wrong results.

# Previous behavior, before the fix:
>>> pl.Series([0, 2, 255, None], dtype=pl.UInt8).index_of(np.uint16(256))
3

Now it does the right thing and errors out. Similarly for other cases of lossy casting, not all of which were caught when FirstArgLossLess was first implemented.

[codecov]

Codecov Report

❌ Patch coverage is 97.01493% with 2 lines in your changes missing coverage. Please review.
⚠️ Please upload report for BASE (main@9e6e923). Learn more about missing BASE report.

Files with missing lines	Patch %	Lines
...ars-plan/src/plans/conversion/type_coercion/mod.rs	97.01%	2 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #24369   +/-   ##
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  Coverage        ?   81.81%           
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  Files           ?     1683           
  Lines           ?   229094           
  Branches        ?     2943           
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  Hits            ?   187444           
  Misses          ?    40911           
  Partials        ?      739           

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