fix: Ensure hex and bitstring literals work inside SQL IN clauses

[alexander-beedie]

Noticed SQL parsing didn't handle hex & bit string literals consistently between the visit_literal and visit_any_value codepaths, which would cause "IN" clauses using such literals to raise an error.

Factored out some common code, aligned the conversions, and added some test coverage.

[codecov]

Codecov Report

Attention: Patch coverage is 85.71429% with 4 lines in your changes are missing coverage. Please review.

Project coverage is 80.98%. Comparing base (acb601d) to head (53fe744).

❗ Current head 53fe744 differs from pull request most recent head 042583c. Consider uploading reports for the commit 042583c to get more accurate results

Files	Patch %	Lines
crates/polars-sql/src/sql_expr.rs	85.71%	4 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #16101   +/-   ##
=======================================
  Coverage   80.97%   80.98%           
=======================================
  Files        1386     1386           
  Lines      178479   178489   +10     
  Branches     2877     2877           
=======================================
+ Hits       144530   144554   +24     
+ Misses      33458    33444   -14     
  Partials      491      491           

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