[PWGEM/Dilepton] remove unnecessary histogram from single muon QC MC

[dsekihat]

[PWGEM/Dilepton] remove unnecessary histogram from single muon QC MC

[github-actions]

O2 linter results: ❌ 103 errors, ⚠️ 140 warnings, 🔕 0 disabled

[alibuild]

Error while checking build/O2Physics/code-check for 677e2ef at 2026-09-08 16:12:

## sw/BUILD/O2Physics-code-check-latest/log
--
========== List of issues found ==========
++ echo 'Found 3 errors and 12 warnings.'
Found 3 errors and 12 warnings.
++ [[ 3 -gt 0 ]]
++ cat /sw/BUILD/28f283162d809b903eb3edf71d2f7afbf40cfafb/O2Physics-code-check/errors.txt
PWGEM/Dilepton/Core/SingleTrackQCMC.h:90:8: error: constructor does not initialize these fields: ccdb [cppcoreguidelines-pro-type-member-init,-warnings-as-errors]
PWGEM/Dilepton/Core/SingleTrackQCMC.h:885:11: error: if with identical then and else branches [bugprone-branch-clone,-warnings-as-errors]
PWGEM/Dilepton/Core/SingleTrackQCMC.h:1092:11: error: if with identical then and else branches [bugprone-branch-clone,-warnings-as-errors]
++ [[ 12 -gt 0 ]]
++ cat /sw/BUILD/28f283162d809b903eb3edf71d2f7afbf40cfafb/O2Physics-code-check/warnings.txt
PWGEM/Dilepton/Core/SingleTrackQCMC.h:67:10: warning: inclusion of deprecated C++ header 'math.h'; consider using 'cmath' instead [modernize-deprecated-headers]
PWGEM/Dilepton/Core/SingleTrackQCMC.h:266:20: warning: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays]
PWGEM/Dilepton/Core/SingleTrackQCMC.h:267:20: warning: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays]
PWGEM/Dilepton/Core/SingleTrackQCMC.h:269:3: warning: use '= default' to define a trivial destructor [modernize-use-equals-default]
PWGEM/Dilepton/Core/SingleTrackQCMC.h:478:39: warning: use nullptr [modernize-use-nullptr]
PWGEM/Dilepton/Core/SingleTrackQCMC.h:479:43: warning: use nullptr [modernize-use-nullptr]
PWGEM/Dilepton/Core/SingleTrackQCMC.h:480:24: warning: statement should be inside braces [readability-braces-around-statements]
PWGEM/Dilepton/Core/SingleTrackQCMC.h:626:14: warning: redundant boolean literal in conditional return statement [readability-simplify-boolean-expr]
PWGEM/Dilepton/Core/SingleTrackQCMC.h:627:7: warning: do not use 'else' after 'return' [readability-else-after-return]
PWGEM/Dilepton/Core/SingleTrackQCMC.h:844:7: warning: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays]
PWGEM/Dilepton/Core/SingleTrackQCMC.h:968:7: warning: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays]
PWGEM/Dilepton/Core/SingleTrackQCMC.h:1062:7: warning: do not declare C-style arrays, use 'std::array' instead [modernize-avoid-c-arrays]
++ [[ 3 -gt 0 ]]
++ exit 1
--

Full log here.

[alibuild]

Auto-approving on behalf of @dsekihat.