Fix missing return in v1v2_observable_df noise distribution merge#502

dweindl merged 2 commits into

PEtab-dev:mainPEtab-dev/libpetab-python:mainfrom

dweindl:fix/v1v2-observable-df-noise-distributiondweindl/libpetab-python:fix/v1v2-observable-df-noise-distributionCopy head branch name to clipboard