[PWGLF] Rename source file nucleitpcpbpb.cxx to nucleitpcPbPb.cxx and clean the code with few changes (#17177)

Co-authored-by: ALICE Action Bot <alibuild@cern.ch>

Author: jtanwar2212

PWGLF/Tasks/Nuspex/CMakeLists.txt

@@ -70,7 +70,7 @@ o2physics_add_dpl_workflow(spectra-tpc-tiny
     COMPONENT_NAME Analysis)
 
 o2physics_add_dpl_workflow(nuclei-tpcspectra
-    SOURCES nucleitpcpbpb.cxx
+    SOURCES nucleitpcPbPb.cxx
     PUBLIC_LINK_LIBRARIES O2Physics::AnalysisCore
     COMPONENT_NAME Analysis)