Discovery: add NbSSe (1NbSSe-2)

active_challenge.csv

@@ -259,3 +259,4 @@ OSC-00255,2SnNb3Se6-1,2SnNb3Se6-1,Nb6Se12Sn2,discovery,light,,ok,0.05538,0.44304
 OSC-00256,2SiNb3Te6-1,2SiNb3Te6-1,Nb6Si2Te12,discovery,light,,ok,0.02689,0.21512,8.0,-1.8913,1.29,,0.2778,0.48728,gaussian_dos_scf_mesh,0.05849,,
 OSC-00257,2SnNb3Te6-1,2SnNb3Te6-1,Nb6Sn2Te12,discovery,light,,ok,0.03658,0.29264,8.0,-1.9777,1.292,,0.2778,0.48698,gaussian_dos_scf_mesh,0.05849,,
 OSC-00258,1NbS2-2,1NbS2-2,NbS2,discovery,light,,ok,0.28093,2.24744,8.0,-0.2694,0.9591,,0.0556,0.86577,gaussian_dos_scf_mesh,0.04523,,
+OSC-00259,1NbSSe-2,1NbSSe-2,NbSSe,discovery,light,,ok,0.27669,2.21352,8.0,-0.3628,0.9811,,0.0556,1.01722,gaussian_dos_scf_mesh,0.04523,,