[expo][assets] Register the Expo asset plugin with Metro

Expo comes with an asset plugin that adds the MD5 checksums of asset files to each asset object. This is used when uploading hosted assets.

We need to extend Metro and the RN CLI parameters to support passing in plugins from Expo CLI but for SDK 31 we'll patch RN directly.

local-cli/core/index.js

@@ -132,6 +132,15 @@ async function getCliConfig(): Promise<RNConfig> {
   );
 
   config.transformer.assetRegistryPath = ASSET_REGISTRY_PATH;
+
+  // NOTE(expo): include the Expo asset plugin to support static resources
+  try {
+    let expoAssetPluginPath = require.resolve('expo/tools/hashAssetFiles');
+    config.transformer.assetPlugins = [expoAssetPluginPath];
+  } catch (e) {
+    console.warn('Could not find the "expo" package in your project when configuring the packager');
+  }
+
   config.resolver.hasteImplModulePath =
     config.resolver.hasteImplModulePath || defaultConfig.hasteImplModulePath;
   config.resolver.platforms = config.resolver.platforms