feat: added edge case tests for v2 writer

[raunaks13]

1. Writes with zero batches
2. Writes with zero rows (all batches)
3. Writes with zero rows (some batches)

Not sure whether we should validate the data after writing the file? I didn't include it since the original test didn't either

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 91.22807% with 10 lines in your changes are missing coverage. Please review.

Project coverage is 79.85%. Comparing base (7d9dbda) to head (762370a). Report is 12 commits behind head on main.

Files	Patch %	Lines
rust/lance-file/src/v2/writer.rs	91.22%	0 Missing and 10 partials :warning:

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2365      +/-   ##
==========================================
- Coverage   80.69%   79.85%   -0.85%     
==========================================
  Files         192      191       -1     
  Lines       56193    53135    -3058     
  Branches    56193    53135    -3058     
==========================================
- Hits        45344    42430    -2914     
+ Misses       8221     8194      -27     
+ Partials     2628     2511     -117     

Flag	Coverage Δ
unittests	79.85% <91.22%> (-0.85%)	:arrow_down:

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[raunaks13]

Not required any longer, closing