fix: improve `PossiblyNoBeam` assignment for RG-A Sp19 #187

Job	Run time
get_datasets	11s
groovy_vs_cpp (pass1/rga_fa18_inbending)	2m 38s
groovy_vs_cpp (pass1/rga_fa18_outbending)	2m 43s
groovy_vs_cpp (pass1/rga_sp19)	2m 39s
groovy_vs_cpp (pass1/rgb_fa19)	2m 38s
groovy_vs_cpp (pass1/rgb_sp19)	2m 38s
groovy_vs_cpp (pass1/rgb_wi20)	2m 38s
groovy_vs_cpp (pass1/rgc_su22)	2m 39s
groovy_vs_cpp (pass1/rgk_fa18_6.5GeV)	2m 37s
groovy_vs_cpp (pass1/rgk_fa18_7.5GeV)	2m 38s
groovy_vs_cpp (pass1/rgm_fa21)	2m 39s
groovy_vs_cpp (pass2/rga_sp19)	2m 38s
report	1s
	29m 17s

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