fix: rework list encoder to handle list-struct

[westonpace]

We had previously scanned through the items pages triggering decoding in a manner that was very similar to the struct decoder but incomplete.

Now, we reuse the struct decoder in the list decoder. So the "indirect schedule & decode" is nearly identical to a direct schedule & decode. This removed some near-duplicate code and makes it so that we can handle list-struct (or list-anything)

This also forced us to fix another issue that was preventing us from decoding files with more than 2^32 rows.

[westonpace]

Leaving in draft until #2337 is resolved.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 89.64401% with 32 lines in your changes are missing coverage. Please review.

Project coverage is 80.77%. Comparing base (648adf8) to head (6c1f01b).
Report is 3 commits behind head on main.

Files	Patch %	Lines
rust/lance-encoding/src/encodings/logical/list.rs	82.53%	4 Missing and 7 partials ⚠️
rust/lance-encoding/src/decoder.rs	80.00%	6 Missing and 1 partial ⚠️
rust/lance-file/src/v2/reader.rs	50.00%	5 Missing ⚠️
...ust/lance-encoding/src/encodings/logical/struct.rs	97.50%	1 Missing and 3 partials ⚠️
rust/lance-encoding/src/testing.rs	89.74%	2 Missing and 2 partials ⚠️
...-encoding/src/encodings/logical/fixed_size_list.rs	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2344      +/-   ##
==========================================
+ Coverage   80.75%   80.77%   +0.01%     
==========================================
  Files         192      192              
  Lines       56367    56381      +14     
  Branches    56367    56381      +14     
==========================================
+ Hits        45521    45543      +22     
- Misses       8179     8197      +18     
+ Partials     2667     2641      -26     

Flag	Coverage Δ
unittests	80.77% <89.64%> (+0.01%)	⬆️

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