update home notice expected text to match updated text

this was changed in the previous commit because the onboarding screen is no longer in the app and it was updated to remove the page and content to reflect that.

tests/cypress/integration/notifications.cy.js

@@ -310,7 +310,7 @@ describe( 'Notifications', () => {
 		).should( 'be.visible' );
 		cy.get(
 			'.newfold-notifications-wrapper #notification-test-home'
-		).contains( 'display on home and onboarding screens' );
+		).contains( 'display on home screen only' );
 
 		cy.get(
 			'#notification-test-home button.notice-dismiss[data-action="close"]'