perf: Lazy decompress Parquet pages

[coastalwhite]

This only decompresses pages if they are actually going to be read from. This is only possible for unnested values and should save quite some time on slice pushdown and parallel=prefiltered.

[codecov]

Codecov Report

Attention: Patch coverage is 72.41379% with 8 lines in your changes missing coverage. Please review.

Project coverage is 80.35%. Comparing base (a601ccf) to head (7c23f61).
Report is 21 commits behind head on main.

Files	Patch %	Lines
...tes/polars-parquet/src/parquet/read/compression.rs	71.42%	4 Missing ⚠️
.../polars-parquet/src/arrow/read/deserialize/null.rs	71.42%	2 Missing ⚠️
...parquet/src/arrow/read/deserialize/nested_utils.rs	75.00%	1 Missing ⚠️
...rs-parquet/src/arrow/read/deserialize/utils/mod.rs	75.00%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #18326   +/-   ##
=======================================
  Coverage   80.35%   80.35%           
=======================================
  Files        1501     1501           
  Lines      199236   199241    +5     
  Branches     2837     2837           
=======================================
+ Hits       160087   160108   +21     
+ Misses      38623    38607   -16     
  Partials      526      526           

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