[PWGHF] Add EMCal-registered event selection for hadrons in event mixing

[rashigupt]

This update adds the EMCal-registered event selection when filling the hadron table used for event mixing in CorrelatorHfehadron.cxx. This ensures that only hadrons from EMCal-registered events are included in the mixed-event correlation analysis.

[github-actions]

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

[alibuild]

Error while checking build/O2Physics/o2 for 655e3b0 at 2026-09-03 11:30:

## sw/BUILD/O2Physics-latest/log
c++: fatal error: Killed signal terminated program cc1plus
c++: fatal error: Killed signal terminated program cc1plus
ninja: build stopped: subcommand failed.

Full log here.

[alibuild]

Error while checking build/O2Physics/code-check for 655e3b0 at 2026-09-04 01:40:

## sw/BUILD/O2Physics-code-check-latest/log
--
========== List of issues found ==========
++ echo 'Found 2 errors and 0 warnings.'
Found 2 errors and 0 warnings.
++ [[ 2 -gt 0 ]]
++ cat /sw/BUILD/31fb27c457cb089657ce2691db25a824f439791d/O2Physics-code-check/errors.txt
PWGHF/HFC/TableProducer/correlatorHfeHadrons.cxx:288:9: error: variable 'cntEle' set but not used [clang-diagnostic-unused-but-set-variable,-warnings-as-errors]
PWGHF/HFC/TableProducer/correlatorHfeHadrons.cxx:302:45: error: repeated branch body in conditional chain [bugprone-branch-clone,-warnings-as-errors]
++ [[ 0 -gt 0 ]]
++ [[ 2 -gt 0 ]]
++ exit 1
--

Full log here.

[rashigupt]

Dear Expert, the code builds successfully on my local machine.

[vkucera]

Dear Expert, the code builds successfully on my local machine.

You still have a compilation warning.

[alibuild]

Error while checking build/O2Physics/code-check for a97a334 at 2026-09-08 03:16:

## sw/BUILD/O2Physics-code-check-latest/log
--
========== List of issues found ==========
++ echo 'Found 1 errors and 0 warnings.'
Found 1 errors and 0 warnings.
++ [[ 1 -gt 0 ]]
++ cat /sw/BUILD/45aa122dc4712ae78ea55c45156a4963db00f77b/O2Physics-code-check/errors.txt
PWGHF/HFC/TableProducer/correlatorHfeHadrons.cxx:301:45: error: repeated branch body in conditional chain [bugprone-branch-clone,-warnings-as-errors]
++ [[ 0 -gt 0 ]]
++ [[ 1 -gt 0 ]]
++ exit 1
--

Full log here.

[rashigupt]

Dear expert , please approve and merge the code.