[PWGHF] Implement minor changes to B2JPsi code

[fgrosa]

@fchinu

[github-actions]

O2 linter results: ❌ 0 errors, ⚠️ 1 warnings, 🔕 0 disabled

[alibuild]

Auto-approving on behalf of @fgrosa.

[alibuild]

Error while checking build/O2Physics/code-check for 1a38580 at 2026-08-18 22:56:

## sw/BUILD/O2Physics-code-check-latest/log
--
========== List of issues found ==========
++ echo 'Found 4 errors and 0 warnings.'
Found 4 errors and 0 warnings.
++ [[ 4 -gt 0 ]]
++ cat /sw/BUILD/7c8dc66e8c7df21fa91df2f456d173c7fe8e9d90/O2Physics-code-check/errors.txt
PWGHF/D2H/TableProducer/candidateCreatorBToJpsiReduced.cxx:39:1: error: included header Track.h is not used directly [misc-include-cleaner,-warnings-as-errors]
PWGHF/D2H/TableProducer/dataCreatorJpsiHadReduced.cxx:106:65: error: variable 'partlyRecoDecayMapMuMu' is non-const and globally accessible, consider making it const [cppcoreguidelines-avoid-non-const-global-variables,-warnings-as-errors]
PWGHF/D2H/TableProducer/dataCreatorJpsiHadReduced.cxx:112:65: error: variable 'partlyRecoDecayMapEE' is non-const and globally accessible, consider making it const [cppcoreguidelines-avoid-non-const-global-variables,-warnings-as-errors]
PWGHF/D2H/TableProducer/dataCreatorJpsiHadReduced.cxx:1015:12: error: no header providing "TESTBIT" is directly included [misc-include-cleaner,-warnings-as-errors]
++ [[ 0 -gt 0 ]]
++ [[ 4 -gt 0 ]]
++ exit 1
--

Full log here.