Boxmenu prevents adapt executing

[StuartNicholls]

Subject of the issue

Boxmenu prevents adapt from executing if background-images haven't been specified in the JSON before compiling.

Your environment

Latest versions of boxmenu

Steps to reproduce

Instal adapt from the comand line. Compile

Expected behaviour

Needs a break clause if (!backgroundImages) return but needs separating out in to functions or reconfiguring..

adapt-contrib-boxMenu/js/BoxMenuView.js

Lines 9 to 19 in 182b229

	const backgroundImages = this.model.get('_boxMenu')?._backgroundImage;
	const backgroundImage = backgroundImages[`_${device.screenSize}`] ?? backgroundImages._small;
	const textAlignment = this.model.get('_boxMenu')?._menuHeader?._textAlignment;
	return [
	`${super.className()} boxmenu`,
	backgroundImage && 'has-bg-image',
	textAlignment._title && `title-align-${textAlignment._title}`,
	textAlignment._body && `body-align-${textAlignment._body}`,
	textAlignment._instruction && `instruction-align-${textAlignment._instruction}`
	].join(' ');

..as that will then prevent textAlignment being executed.

[oliverfoster]