Gutenboarding: Set lang/dir in browser

[sirreal]

Part of #37665
Follow-up to #39410

lang and dir should be correctly set in Gutenboarding. See:

wp-calypso/client/lib/i18n-utils/switch-locale.js

Lines 82 to 90 in f1e7964

	function setLocaleInDOM() {
	const htmlLangAttribute = getHtmlLangAttribute();
	const isRTL = i18n.isRtl();
	document.documentElement.lang = htmlLangAttribute;
	document.documentElement.dir = isRTL ? 'rtl' : 'ltr';
	document.body.classList[ isRTL ? 'add' : 'remove' ]( 'rtl' );
	switchWebpackCSS( isRTL );
	}

[ramonjd]

Is this issue still valid given https://github.com/Automattic/wp-calypso/blob/master/client/landing/gutenboarding/components/window-locale-effect-manager/index.tsx?

[sirreal]

Closing, this does seem to be resolved. I tested with routes like /new/es and /new/he as well as switching via the language picker.