Fixed App constructor type

packages/realm-web/src/index.ts

@@ -21,7 +21,7 @@ import { App } from "./App";
 const appCache: { [id: string]: Realm.App } = {};
 
 /**
- * Get or create a Realm App from an id.
+ * Get or create a singleton Realm App from an id.
  *
  * @param id The Realm App id visible from the MongoDB Realm UI or a configuration
  * @returns The Realm App instance. Calling this function multiple times with the same id will return the same instance.
@@ -30,9 +30,7 @@ export function app(id: string) {
     if (id in appCache) {
         return appCache[id];
     } else {
-        // Ensures the App has the correct constructor type signature
-        const AppConstructor: Realm.AppConstructor = App;
-        const instance = new AppConstructor(id);
+        const instance = new App(id);
         appCache[id] = instance;
         return instance;
     }

types/app.d.ts

@@ -106,19 +106,16 @@ declare namespace Realm {
         // TODO: Add providerCapabilities?
     }
 
-    /**
-     * The constructor of MongoDB Realm App.
-     */
-    type AppConstructor = new <
-        FunctionsFactoryType extends object = DefaultFunctionsFactory
-    >(
-        idOrConfiguration: string | AppConfiguration,
-    ) => App<FunctionsFactoryType>;
-
     /**
      * A MongoDB Realm App.
      */
     class App<FunctionsFactoryType extends object = DefaultFunctionsFactory, CustomDataType extends object = any> {
+        /**
+         * Construct a MongoDB Realm App.
+         *
+         * @param idOrConfiguration The id string or configuration for the app.
+         */
+        constructor(idOrConfiguration: string | AppConfiguration);
 
         /**
          *