Update grid.cc #8667

Job	Run time
classicmode_1d_3dgrid	9m 14s
classicmode_3d	8m 44s
kilonova_1d_1dgrid	4m 25s
kilonova_1d_3dgrid	4m 28s
kilonova_2d_2dgrid	6m 41s
kilonova_2d_2dgrid_barnesthermalisation	6m 20s
kilonova_2d_2dgrid_expansionopac	4m 42s
kilonova_2d_2dgrid_xcomgammaphotoion	4m 54s
kilonova_2d_3dgrid	6m 39s
nebular_1d_3dgrid	11m 9s
nebular_1d_3dgrid_limitbfest	13m 16s
combine_checksums	16s
	1h 20m 48s

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