removing entry, rootDir from defaultPlugins

Summary:
When bundling default plugins, we create a JSON-file containing information about the plugin and where to require it from. This information contained two filed: `entry` and `rootDir`, which were written while bundling the plugins. Because the plugins are bundled on Sandcastle, this was a path on the Sandcastle machine.

This also happened for the OSS version, see the screenshot from a GitHub issue.
Entry and rootDir are only used during the build process and not needed afterwards, so it is save to remove them from the JSON.

https://pxl.cl/qQSx

Reviewed By: passy

Differential Revision: D14165679

fbshipit-source-id: 4e7c5ac25652758ccfc3a459f4dd197254c6f897

scripts/build-utils.js

@@ -30,9 +30,9 @@ function compileDefaultPlugins(defaultPluginDir) {
       fs.writeFileSync(
         path.join(defaultPluginDir, 'index.json'),
         JSON.stringify(
-          defaultPlugins.map(plugin => ({
+          defaultPlugins.map(({entry, rootDir, out, ...plugin}) => ({
             ...plugin,
-            out: path.parse(plugin.out).base,
+            out: path.parse(out).base,
           })),
         ),
       ),