fix: fix two cases in the v2 decoder where the decode order didn't match the scheduling priority

[westonpace]

This could lead to deadlocks when the io_buffer_size is small (or when page sizes are very large).

Unfortunately, this is not the ideal scheduling algorithm, it uses too much RAM, but it's better to do that than deadlock. Details in #2753

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 85.23490% with 22 lines in your changes missing coverage. Please review.

Project coverage is 79.15%. Comparing base (7284521) to head (a53167a).

Files	Patch %	Lines
...ust/lance-encoding/src/encodings/logical/struct.rs	82.75%	8 Missing and 2 partials ⚠️
rust/lance-encoding/src/decoder.rs	85.29%	5 Missing ⚠️
rust/lance-encoding/src/encodings/logical/list.rs	87.50%	1 Missing and 3 partials ⚠️
rust/lance-encoding/src/testing.rs	82.35%	1 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2754      +/-   ##
==========================================
+ Coverage   79.13%   79.15%   +0.02%     
==========================================
  Files         227      227              
  Lines       67398    67441      +43     
  Branches    67398    67441      +43     
==========================================
+ Hits        53338    53386      +48     
+ Misses      10956    10949       -7     
- Partials     3104     3106       +2     

Flag	Coverage Δ
unittests	79.15% <85.23%> (+0.02%)	⬆️

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