Fixing typo in recently added ReblockGVCFs argument

[meganshand]

No description provided.

[gatk-bot]

Github actions tests reported job failures from actions build 4926586986
Failures in the following jobs:

Test Type	JDK	Job ID	Logs
cloud	17.0.6+10	4926586986.10	logs
cloud	17.0.6+10	4926586986.10	logs

[codecov]

Codecov Report

Merging #8308 (57f5a70) into master (ba483e3) will increase coverage by 12.867%.
The diff coverage is n/a.

Additional details and impacted files

@@               Coverage Diff                @@
##              master     #8308        +/-   ##
================================================
+ Coverage     73.413%   86.280%   +12.867%     
- Complexity     34267     39514      +5247     
================================================
  Files           2354      2354                
  Lines         185399    185399                
  Branches       20444     20444                
================================================
+ Hits          136107    159962     +23855     
+ Misses         42561     18246     -24315     
- Partials        6731      7191       +460     

Impacted Files	Coverage Δ
...bender/tools/walkers/variantutils/ReblockGVCF.java	80.714% <ø> (ø)

... and 472 files with indirect coverage changes