guard against cases where gd.emit got purged
guard against cases where gd.emit got purged

... before native 'webgl_contextlost' is triggered.

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