update Modebar.hasButtons for cases where buttons haven't been drawn yet
update Modebar.hasButtons for cases where buttons haven't been drawn yet

iongroup/plotly.js,asolagmbh/plotly.js,etpinard/plotly.js,aburato/plotly.js,plotly/plotly.js,asolagmbh/plotly.js,asolagmbh/plotly.js,aburato/plotly.js,plotly/plotly.js,iongroup/plotly.js,plotly/plotly.js,etpinard/plotly.js,etpinard/plotly.js,plotly/plotly.js,iongroup/plotly.js