Fix exception `initial databaseList request failed: T.sort is not a f…

…unction`

Summary: Exception showed up in our monitoring. The only `.sort` that happens in that request/response sequence is the one updated. Didn't get to the root of this, but likely the plugin returns nothing rather than an empty array when no databases present?

Reviewed By: LukeDefeo

Differential Revision: D47665268

fbshipit-source-id: 3f8dea591db3e6cb5d4e0d09f893a177ad4f642e

desktop/plugins/public/databases/index.tsx

@@ -108,7 +108,7 @@ export function plugin(client: PluginClient<Events, Methods>) {
   const updateDatabases = (event: {
     databases: Array<{name: string; id: number; tables: Array<string>}>;
   }) => {
-    const updates = event.databases;
+    const updates = event.databases ?? [];
     const state = pluginState.get();
     const databases = updates.sort((db1, db2) => db1.id - db2.id);
     const selectedDatabase =