Add aria-hidden=true attribute to hidden iframe for resizing (#4400)
Add aria-hidden=true attribute to hidden iframe for resizing (#4400)

Add aria-hidden=true attribute to hidden iframe for resizing. This prevents screen readers in ItemMode from navigating to the hidden iframe.

simonbrunel/Chart.js,supernovel/Chart.js,chartjs/Chart.js,touletan/Chart.js,jtcorbett/Chart.js,ldwformat/Chart.js,touletan/Chart.js,panzarino/Chart.js,simonbrunel/Chart.js,ldwformat/Chart.js,touletan/Chart.js,chartjs/Chart.js,touletan/Chart.js,supernovel/Chart.js,chartjs/Chart.js,nnnick/Chart.js,panzarino/Chart.js,chartjs/Chart.js,jtcorbett/Chart.js