don't warn if `dependency.api.polyfill` is undefined

incubator/polyfills/src/dependency.ts

@@ -37,11 +37,16 @@ export function getDependencyPolyfills(context: Context): string[] {
     try {
       const config = require.resolve(`${name}/react-native.config.js`, options);
       const polyfill = require(config).dependency?.api?.polyfill;
+      if (polyfill == null) {
+        continue;
+      }
+
       const absolutePath = resolvePath(path.dirname(config), polyfill);
       if (!absolutePath) {
         error(`${name}: invalid polyfill path: ${polyfill}`);
         continue;
       }
+
       if (!fs.existsSync(absolutePath)) {
         error(`${name}: no such polyfill: ${polyfill}`);
         continue;

incubator/polyfills/test/__fixtures__/node_modules/no-polyfill/package.json

@@ -0,0 +1,4 @@
+{
+  "name": "no-polyfill",
+  "version": "1.0.0"
+}

incubator/polyfills/test/__fixtures__/node_modules/no-polyfill/react-native.config.js

@@ -0,0 +1,7 @@
+module.exports = {
+  dependency: {
+    api: {
+      polyfill: undefined,
+    },
+  },
+};