Revert "Remove legacy www config from Rollup build (#18016)"

This reverts commit 529e58a.

Author: bvaughn

scripts/rollup/build.js

@@ -541,6 +541,11 @@ async function createBundle(bundle, bundleType) {
       bundle.moduleType,
       pureExternalModules
     ),
+    // We can't use getters in www.
+    legacy:
+      bundleType === FB_WWW_DEV ||
+      bundleType === FB_WWW_PROD ||
+      bundleType === FB_WWW_PROFILING,
   };
   const [mainOutputPath, ...otherOutputPaths] = Packaging.getBundleOutputPaths(
     bundleType,