Do not load installed plugins in dev mode by default

Summary: Installed plugins loaded and make it impossible to debug plugin changes. We need to disable them by default for `yarn start`. To debug plugin installation and auto-update, need to use command `yarn start --plugin-auto-update` instead.

Reviewed By: passy

Differential Revision: D25639345

fbshipit-source-id: 99b59a90dc09ac33a3604487fe501774e5e6fc39

desktop/app/src/utils/loadDynamicPlugins.tsx

@@ -41,7 +41,9 @@ export default async function loadDynamicPlugins(): Promise<
     ).map((p: any) => p.name) as string[],
   );
   const [installedPlugins, unfilteredSourcePlugins] = await Promise.all([
-    getInstalledPlugins(),
+    process.env.FLIPPER_DISABLE_PLUGIN_AUTO_UPDATE
+      ? Promise.resolve([])
+      : getInstalledPlugins(),
     getSourcePlugins(),
   ]);
   const sourcePlugins = unfilteredSourcePlugins.filter(