If MCEvent not available, reject digits with labelID out of MCStack
If MCEvent not available, reject digits with labelID out of MCStack

HLT calls ITS clusterizer from the AliSimulation, in this case we cannot use the MCEvent to validate
digits labels => if the MC event not available use current MC stack to reject all digits with labels
exceeding number of tracks in the stack.

miranov25/AliRoot,coppedis/AliRoot,coppedis/AliRoot,mkrzewic/AliRoot,ecalvovi/AliRoot,shahor02/AliRoot,coppedis/AliRoot,ALICEHLT/AliRoot,sebaleh/AliRoot,sebaleh/AliRoot,mkrzewic/AliRoot,ecalvovi/AliRoot,mkrzewic/AliRoot,alisw/AliRoot,alisw/AliRoot,shahor02/AliRoot,alisw/AliRoot,shahor02/AliRoot,sebaleh/AliRoot,shahor02/AliRoot,miranov25/AliRoot,ALICEHLT/AliRoot,shahor02/AliRoot,ALICEHLT/AliRoot,alisw/AliRoot,ecalvovi/AliRoot,miranov25/AliRoot,coppedis/AliRoot,ecalvovi/AliRoot,miranov25/AliRoot,mkrzewic/AliRoot,coppedis/AliRoot,alisw/AliRoot,miranov25/AliRoot,alisw/AliRoot,mkrzewic/AliRoot,ALICEHLT/AliRoot,mkrzewic/AliRoot,coppedis/AliRoot,sebaleh/AliRoot,mkrzewic/AliRoot,miranov25/AliRoot,sebaleh/AliRoot,ecalvovi/AliRoot,coppedis/AliRoot,miranov25/AliRoot,alisw/AliRoot,shahor02/AliRoot,ALICEHLT/AliRoot,shahor02/AliRoot,ecalvovi/AliRoot,alisw/AliRoot,ecalvovi/AliRoot,ALICEHLT/AliRoot,ALICEHLT/AliRoot,miranov25/AliRoot,sebaleh/AliRoot,coppedis/AliRoot,sebaleh/AliRoot