add error message for when tree-score-threshold is set in ReblockGVCF…

[meganshand]

…s without TREE_SCORE present

Addresses #8203

[gatk-bot]

Github actions tests reported job failures from actions build 4244812025
Failures in the following jobs:

Test Type	JDK	Job ID	Logs
integration	11.0.11+9	4244812025.12	logs
integration	8	4244812025.0	logs

[codecov]

Codecov Report

Merging #8218 (fbdeba4) into master (b7f24ff) will increase coverage by 0.004%.
The diff coverage is 100.000%.

Additional details and impacted files

@@               Coverage Diff               @@
##              master     #8218       +/-   ##
===============================================
+ Coverage     86.652%   86.655%   +0.004%     
- Complexity     39151     39169       +18     
===============================================
  Files           2346      2346               
  Lines         183621    183670       +49     
  Branches       20148     20152        +4     
===============================================
+ Hits          159111    159160       +49     
- Misses         17447     17450        +3     
+ Partials        7063      7060        -3     

Impacted Files	Coverage Δ
...bender/tools/walkers/variantutils/ReblockGVCF.java	80.340% <100.000%> (+0.096%)	⬆️
...lkers/variantutils/ReblockGVCFIntegrationTest.java	98.052% <100.000%> (+0.059%)	⬆️
...ls/walkers/qc/TransferReadTagsIntegrationTest.java	94.118% <0.000%> (-1.882%)	⬇️
...der/tools/walkers/variantutils/SelectVariants.java	83.619% <0.000%> (-0.292%)	⬇️
...institute/hellbender/utils/read/FlowBasedRead.java	53.600% <0.000%> (-0.093%)	⬇️
...org/broadinstitute/hellbender/engine/GATKTool.java	90.083% <0.000%> (ø)
...itute/hellbender/tools/LocalAssemblerUnitTest.java	92.448% <0.000%> (ø)
...nder/engine/filters/VariantTypesVariantFilter.java	100.000% <0.000%> (ø)
...rs/variantutils/SelectVariantsIntegrationTest.java	96.959% <0.000%> (+0.031%)	⬆️
...e/hellbender/utils/read/FlowBasedReadUnitTest.java	95.402% <0.000%> (+0.108%)	⬆️
... and 3 more

[jamesemery]

This looks good... i'm a little worried as to why the tool is partiularly slow when the annotation isn't present but this seems like a good