fix(Avatar): fall back to initials when imageUrl is an empty string

An empty string passed `typeof imageUrl === 'string'`, so the component
rendered `<img src="">`, which makes the browser attempt to load the
current document URL as an image. Add a truthy check so empty strings
fall through to the initials/icon fallback path.

Author: oliverlaz

src/components/Avatar/Avatar.tsx

@@ -66,7 +66,7 @@ export const Avatar = ({
     return initials;
   }, [nameString, size]);
 
-  const showImage = typeof imageUrl === 'string' && !error;
+  const showImage = typeof imageUrl === 'string' && imageUrl && !error;
 
   return (
     <div

src/components/Avatar/__tests__/Avatar.test.tsx

@@ -57,6 +57,14 @@ describe('Avatar', () => {
     expect(queryByTestId(AVATAR_IMG_TEST_ID)).not.toBeInTheDocument();
   });
 
+  it('should render fallback when imageUrl is an empty string', () => {
+    const { getByTestId, queryByTestId } = render(
+      <Avatar imageUrl='' size='md' userName='frank N. Stein' />,
+    );
+    expect(queryByTestId(AVATAR_IMG_TEST_ID)).not.toBeInTheDocument();
+    expect(getByTestId(AVATAR_FALLBACK_TEST_ID)).toHaveTextContent('fS');
+  });
+
   it('should call onClick prop on user click', () => {
     const onClick = vi.fn();