fix slice query execution in PartTreeDatastoreQuery

[dmitry-s]

fixes failing CI test

@viniciusccarvalho FYI this PR fixes issues introduced in #2437

[sonarcloud]

Kudos, SonarCloud Quality Gate passed!

0 Bugs
0 Vulnerabilities (and 0 Security Hotspots to review)
0 Code Smells

100.0% Coverage
0.0% Duplication

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[codecov]

Codecov Report

Merging #2452 into master will decrease coverage by 0.02%.
The diff coverage is 100.00%.

@@             Coverage Diff              @@
##             master    #2452      +/-   ##
============================================
- Coverage     74.05%   74.03%   -0.03%     
+ Complexity     2120     2119       -1     
============================================
  Files           264      264              
  Lines          7662     7663       +1     
  Branches        791      790       -1     
============================================
- Hits           5674     5673       -1     
- Misses         1620     1622       +2     
  Partials        368      368              

Flag	Coverage Δ	Complexity Δ
#unittests	74.03% <100.00%> (-0.03%)	2119.00 <0.00> (-1.00)

Impacted Files	Coverage Δ	Complexity Δ
...store/repository/query/PartTreeDatastoreQuery.java	91.44% <100.00%> (+0.04%)	50.00 <0.00> (-1.00)	⬆️
...tastore/GcpDatastoreEmulatorAutoConfiguration.java	65.51% <0.00%> (-6.90%)	6.00% <0.00%> (ø%)

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