chore(spark): fix typo in writer

[jasinliu]

Reason for this PR

As title.

What changes are included in this PR?

Are these changes tested?

Are there any user-facing changes?

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 80.00000% with 1 line in your changes missing coverage. Please review.

Project coverage is 74.28%. Comparing base (b1ebb8e) to head (9499450).

Files with missing lines	Patch %	Lines
...n/scala/org/apache/graphar/writer/EdgeWriter.scala	66.66%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@              Coverage Diff              @@
##               main     #648       +/-   ##
=============================================
+ Coverage     62.50%   74.28%   +11.78%     
- Complexity        0      226      +226     
=============================================
  Files            60       29       -31     
  Lines          8480     2749     -5731     
  Branches        877      179      -698     
=============================================
- Hits           5300     2042     -3258     
+ Misses         3180      551     -2629     
- Partials          0      156      +156     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[SemyonSinchenko]

LGTM, thanks!