Change error wording to remove "Promise elements"

packages/react-reconciler/src/ReactFiberBeginWork.js

@@ -844,7 +844,7 @@ function mountLazyComponent(
       invariant(
         false,
         'Element type is invalid. Received a promise that resolves to: %s. ' +
-          'Promise elements must resolve to a class or function.',
+          'Lazy element type must resolve to a class or function.',
         Component,
       );
     }

packages/react-reconciler/src/__tests__/ReactLazy-test.internal.js

@@ -538,7 +538,7 @@ describe('ReactLazy', () => {
       root.unstable_flushAll();
     }).toThrow(
       'Element type is invalid. Received a promise that resolves to: [object Object]. ' +
-        'Promise elements must resolve to a class or function.',
+        'Lazy element type must resolve to a class or function.',
     );
   });