Reduce number of events in grid ART tests which run both trigger and reco (ATR-20644, ATR-20645)

modified: Trigger/TrigValidation/TrigAnalysisTest/test/test_trigAna_RDOtoAOD_grid.py modified: Trigger/TrigValidation/TrigAnalysisTest/test/test_trigAna_RDOtoAOD_mt1_grid.py modified: Trigger/TrigValidation/TrigAnalysisTest/test/test_trigAna_RDOtoPhysval_grid.py modified: Trigger/TrigValidation/TrigAnalysisTest/test/test_trigAna_RDOtoPhysval_mt1_grid.py modified: Trigger/TrigValidation/TrigAnalysisTest/test/test_trigAna_RDOtoT0Mon_mt1_grid.py