Fix bless when cprnc file is not created

[mkstratos]

hist_utils._compare_hists expects the cprnc_log_file to be None if the log file is not created and success = False

Currently results in the error when blessing MVKO test:

ERROR: Command: 
'/bin/cp -f /lcrc/group/e3sm2/e3smtest/scratch/chrys/MVKO_PS.T62_oQU240.GMPAS-NYF.chrysalis_intel.C.JNextNbfb20250317_010637/run/MVKO_PS.T62_oQU240.GMPAS-NYF.chrysalis_intel.C.JNextNbfb20250317_010637.cpl.hi.0003-01-01-00000.nc.cprnc.out /lcrc/group/e3sm2/e3smtest/scratch/chrys/J/MVKO_PS.T62_oQU240.GMPAS-NYF.chrysalis_intel.C.JNextNbfb20250317_010637/MVKO_PS.T62_oQU240.GMPAS-NYF.chrysalis_intel.C.JNextNbfb20250317_010637.cpl.hi.0003-01-01-00000.nc.cprnc.out' failed with error '/bin/cp: cannot stat '/lcrc/group/e3sm2/e3smtest/scratch/chrys/MVKO_PS.T62_oQU240.GMPAS-NYF.chrysalis_intel.C.JNextNbfb20250317_010637/run/MVKO_PS.T62_oQU240.GMPAS-NYF.chrysalis_intel.C.JNextNbfb20250317_010637.cpl.hi.0003-01-01-00000.nc.cprnc.out': No such file or directory' from dir '/gpfs/fs1/home/e3smtest/jenkins/workspace/ACME_chrysalis_bless/E3SM/cime'