workflow_ttest currently fails when there are no signifikant proteins after FDR #56
Description
The script fails if significant_after_FDR = TRUE but there are no significant proteins after FDR.
It fails at the generation of candidate boxplots (and later possible also at the generation of the heatmap) because the filtered data is empty.
In this case, we should skip the generation of the plots and give a warning (or alternatively provide an empty plot).