breaking: Remove fallback flow for Metro config defaults (0.73)

Reverts #1896

Author: huntie

packages/cli-plugin-metro/src/tools/getDefaultMetroConfig.ts

@@ -9,7 +9,6 @@ import {
 } from 'metro-config';
 import {CLIError, logger} from '@react-native-community/cli-tools';
 import type {Config} from '@react-native-community/cli-types';
-import getDefaultMetroConfig from './getDefaultMetroConfig';
 import {reactNativePlatformResolver} from './metroPlatformResolver';
 
 export type {Config};
@@ -101,20 +100,11 @@ export default async function loadMetroConfig(
     )
   ) {
     logger.warn(
-      'From React Native 0.72, your metro.config.js file should extend' +
-        "'@react-native/metro-config'. Please see the React Native 0.72 " +
-        'changelog, or copy the template at:\n' +
+      'From React Native 0.73, your metro.config.js file should extend' +
+        "'@react-native/metro-config' or it will fail to build. Please copy " +
+        'the template at:\n' +
         'https://github.com/facebook/react-native/blob/main/packages/react-native/template/metro.config.js',
     );
-    logger.warn('Falling back to internal defaults.');
-
-    const loadedConfig = await loadConfig(
-      {cwd: ctx.root, ...options},
-      // Provide React Native defaults on top of Metro defaults
-      getDefaultMetroConfig(ctx),
-    );
-
-    return mergeConfig(loadedConfig, overrideConfig);
   }
 
   return mergeConfig(