[PWGEM] add new pairQC Task + clean up photonhbt (#17984)

Co-authored-by: Stefanie Mrozinski <stefanie.mrozinski@stud.uni-frankfurt.de>

Author: Steffimro

PWGEM/PhotonMeson/Tasks/CMakeLists.txt

@@ -200,3 +200,8 @@ o2physics_add_dpl_workflow(event-normalization-task
                     SOURCES eventNormalizationTask.cxx
                     PUBLIC_LINK_LIBRARIES O2::Framework O2Physics::AnalysisCore
                     COMPONENT_NAME Analysis)
+
+o2physics_add_dpl_workflow(pair-qc-task
+                    SOURCES pairQcTask.cxx
+                    PUBLIC_LINK_LIBRARIES O2::Framework O2Physics::AnalysisCore O2Physics::PWGEMPhotonMesonCore
+                    COMPONENT_NAME Analysis)