[xdl] set EXPO_TARGET to correct value when starting dev server

packages/xdl/src/Project.ts

@@ -2215,8 +2215,9 @@ async function startDevServerAsync(projectRoot: string, startOptions: StartOptio
   if (startOptions.target) {
     // EXPO_TARGET is used by @expo/metro-config to determine the target when getDefaultConfig is
     // called from metro.config.js and the --target option is used to override the default target.
-    process.env.EXPO_TARGET = options.target;
+    process.env.EXPO_TARGET = startOptions.target;
   }
+
   const { middleware } = await runMetroDevServerAsync(projectRoot, options);
   middleware.use(getManifestHandler(projectRoot));
 }