remove not directly used header

Signed-off-by: Veronika Barbasova <vernika.barbasova@cern.ch>

Author: Veronika Barbasova

PWGLF/Tasks/Resonances/phianalysisTHnSparse.cxx

@@ -49,7 +49,6 @@
 #include <Math/Vector4Dfwd.h>
 #include <TH1.h>
 #include <TH2.h>
-#include <TH3.h>
 #include <TMath.h>
 #include <TString.h>