update type from JSX.Element or string to ReactNode + add test for string based prop

Signed-off-by: Emma Indal <emma.indahl@gmail.com>

packages/core-components/src/layout/ErrorPage/ErrorPage.test.tsx

@@ -32,6 +32,22 @@ describe('<ErrorPage/>', () => {
     expect(getByTestId('go-back-link')).toBeInTheDocument();
   });
 
+  it('should render with additional information of type string', async () => {
+    const { getByText } = await renderInTestApp(
+      <ErrorPage
+        status="404"
+        statusMessage="PAGE NOT FOUND"
+        additionalInfo="This is a string based additional information"
+      />,
+    );
+    expect(
+      getByText(/looks like someone dropped the mic!/i),
+    ).toBeInTheDocument();
+    expect(
+      getByText(/This is a string based additional information/i),
+    ).toBeInTheDocument();
+  });
+
   it('should render with additional information including link', async () => {
     const { getByText } = await renderInTestApp(
       <ErrorPage

packages/core-components/src/layout/ErrorPage/ErrorPage.tsx

@@ -27,7 +27,7 @@ import { MicDrop } from './MicDrop';
 interface IErrorPageProps {
   status: string;
   statusMessage: string;
-  additionalInfo?: string | JSX.Element;
+  additionalInfo?: React.ReactNode;
   supportUrl?: string;
 }