wp-calypso/client/dashboard/components/summary-button-card-footer/style.scss

.components-card-footer.dashboard-summary-button-card-footer {
	padding: 0;

	.summary-button.components-button.has-density-medium {
		border-bottom: none;
		border-bottom-left-radius: inherit;
		border-bottom-right-radius: inherit;
	}
}