LoginPageLayout is overriding `is-paper` class from Vanilla on small screens

[bartaz]

Login page layout is overriding is-paper class from Vanilla on small screens, hardcoding the white background there. It causes project that use this class, but also import react-component style, to have unintentional white background on small screens, where is-paper gray should be used.

This should be removed, or scoped to only apply to this component.

react-components/src/components/LoginPageLayout/LoginPageLayout.scss

Lines 12 to 14 in a2ce1bc

	.is-paper {
	background-color: #fff;
	}