Only override AttributeData.isUnderline when urlId is set
Only override AttributeData.isUnderline when urlId is set

xtermjs/xterm.js,xtermjs/xterm.js,Tyriar/xterm.js,xtermjs/xterm.js,xtermjs/xterm.js,Tyriar/xterm.js,Tyriar/xterm.js,Tyriar/xterm.js,Tyriar/xterm.js,xtermjs/xterm.js