Fix loading of Sandy plugins packaged by flipper-pkg

Summary:
Flipper cannot load Sandy plugins packaged by flipper-pkg, because the latter only expose default export, but Sandy API is using named exports instead ("Component" and "plugin").

This change fixes this by exposing both default and named exports from plugin package.

Reviewed By: passy

Differential Revision: D23815769

fbshipit-source-id: 1dd273b2e7b98bd01148506037066c41ffd19eb8

desktop/pkg-lib/src/runBuild.ts

@@ -46,7 +46,7 @@ export default async function runBuild(
     serializer: {
       ...baseConfig.serializer,
       getRunModuleStatement: (moduleID: string) =>
-        `module.exports = global.__r(${moduleID}).default;`,
+        `module.exports = global.__r(${moduleID});`,
     },
     transformer: {
       ...baseConfig.transformer,