fix: Don't try to load non-existend List/FSL statistics

[coastalwhite]

Fixes #19241.

[codecov]

Codecov Report

Attention: Patch coverage is 75.00000% with 4 lines in your changes missing coverage. Please review.

Project coverage is 78.90%. Comparing base (2c9e503) to head (1197e59).
Report is 9 commits behind head on main.

Files with missing lines	Patch %	Lines
...es/polars-parquet/src/arrow/read/statistics/mod.rs	75.00%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #20388      +/-   ##
==========================================
- Coverage   78.91%   78.90%   -0.01%     
==========================================
  Files        1567     1565       -2     
  Lines      219928   219778     -150     
  Branches     2465     2465              
==========================================
- Hits       173549   173423     -126     
+ Misses      45811    45787      -24     
  Partials      568      568              

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