[PWGEM] checkMCPairTemplate.cxx: Add b2c2l_b2c2l_Hc_ctau histograms which select decays based on life time, fix clang

[PWGEM] checkMCPairTemplate.cxx: Add b2c2l_b2c2l_Hc_ctau histograms which select decays based on life time, fix clang #10141