Update packages/react-native/Libraries/Image/__tests__/Image-test.js

Simplify null check to satisfy flow conditions

Co-authored-by: Peter Abbondanzo <peter@abbondanzo.com>

Author: humaidk2

packages/react-native/Libraries/Image/__tests__/Image-test.js

@@ -352,10 +352,7 @@ describe('Image', () => {
     );
 
     const tree = instance.toJSON();
-    if (tree == null || Array.isArray(tree)) {
-      throw new Error('Expected a single rendered element');
-    }
-    expect(tree.props.headers).toEqual({Authorization: 'Bearer xyz'});
+    expect(tree?.props.headers).toEqual({Authorization: 'Bearer xyz'});
   });
 
   it('forwards source.headers as a top-level prop on Android for array sources', async () => {