AT interface: add checks for array sizes / null pointers
e.g.:
Error in TClonesArray::At: index 1076136973 out of bounds (size: 1084, this: 0x55a333cd4e00) Error in TClonesArray::At: index 1475950162 out of bounds (size: 32609, this: 0x55a333cdcc50) #5 (closed) 0x00002adc1ed65d16 in CbmTofHitsConverter::ProcessData (this=0x55a338c3a290, event=0x55a33ae23f70) at /u/ogolosov/soft/cbmroot/src/core/data/global/CbmGlobalTrack.h:54
Error in TClonesArray::At: index -789787917 out of bounds (size: 12899, this: 0x559573a52b80) #5 (closed) 0x00002adc1ed65d16 in CbmTofHitsConverter::ProcessData (this=0x55a338c3a290, event=0x55a33ae23f70) at /u/ogolosov/soft/cbmroot/src/core/data/global/CbmGlobalTrack.h:54
etc.