fix(SimGR): allow to rin SimGR when no Qobs on SimPer

Refs #43
1 job for 43-allow-to-simulate-a-subperiod-without-discharge-in-simgr in 1 minute and 44 seconds (queued for 8 seconds)
Status Name Job ID Coverage
  Check
passed check_as_cran_patched #191610

00:01:44