fix(SeriesAggreg.OutputsModel): warning on item "Param"

Regression after refactoring in #111
4 jobs for 132-runmodel_lag-add-warmupqsim-to-outputsmodel in 36 minutes and 30 seconds (queued for 26 minutes)
Status Name Job ID Coverage
  Check
passed check_as_cran_patched #191887

00:03:00

passed check_not_cran_patched #191886

00:05:18

 
  Scheduled Tests
passed scheduled_tests_patched #191888

00:27:04

 
  Revdepcheck
passed revdepcheck_patched #191889

00:01:06