fix: empty sparse row in importer

[xiaofan-luan]

fix #40584

parquet bulk writer can not finish 0 dim sparse vector.

[mergify]

@xiaofan-luan

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[codecov]

Codecov Report

Attention: Patch coverage is 94.11765% with 1 line in your changes missing coverage. Please review.

Project coverage is 82.18%. Comparing base (0698d04) to head (bbfe6fd).
Report is 3 commits behind head on master.

Files with missing lines	Patch %	Lines
internal/util/importutilv2/parquet/field_reader.go	94.11%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #40585      +/-   ##
==========================================
+ Coverage   80.54%   82.18%   +1.63%     
==========================================
  Files        1474     1165     -309     
  Lines      207606   179895   -27711     
==========================================
- Hits       167223   147838   -19385     
+ Misses      34317    25993    -8324     
+ Partials     6066     6064       -2     

Components	Coverage Δ
Client	79.74% <ø> (ø)
Core	∅ <ø> (∅)
Go	82.30% <94.11%> (+<0.01%)	⬆️

Files with missing lines	Coverage Δ
internal/util/importutilv2/parquet/field_reader.go	63.33% <94.11%> (-0.16%)	⬇️

... and 346 files with indirect coverage changes

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[czs007]

/approve
/lgtm

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[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: czs007, xiaofan-luan

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