Fix add hline not working for make_subplot if not populated - #5254

Fix add hline not working for make_subplot if not populated#5254

Erikp15 wants to merge 11 commits into

plotly:mainplotly/plotly.py:mainfrom

Erikp15:fix-add_hline-not-workingErikp15/plotly.py:fix-add_hline-not-workingCopy head branch name to clipboard