fix: keep original colnames in the data.frame returned by SeriesAggreg.data.frame

Refs #133
2 jobs for 133-seriesaggreg-reorder-regime-time-series in 8 minutes and 5 seconds (queued for 2 minutes and 37 seconds)
Status Name Job ID Coverage
  Check
passed check_as_cran_patched #186699

00:02:46

passed check_not_cran_patched #186698

00:05:19