use more specific flags type

Signed-off-by: Musaab Elfaqih <musaabe@spotify.com>

packages/frontend-app-api/report.api.md

@@ -34,7 +34,9 @@ export function createSpecializedApp(options?: {
   extensionFactoryMiddleware?:
     | ExtensionFactoryMiddleware
     | ExtensionFactoryMiddleware[];
-  flags?: Record<string, boolean>;
+  flags?: {
+    allowUnknownExtensionConfig?: boolean;
+  };
 }): {
   apis: ApiHolder;
   tree: AppTree;

packages/frontend-app-api/src/wiring/createSpecializedApp.tsx

@@ -208,7 +208,7 @@ export function createSpecializedApp(options?: {
   extensionFactoryMiddleware?:
     | ExtensionFactoryMiddleware
     | ExtensionFactoryMiddleware[];
-  flags?: Record<string, boolean>;
+  flags?: { allowUnknownExtensionConfig?: boolean };
 }): { apis: ApiHolder; tree: AppTree } {
   const config = options?.config ?? new ConfigReader({}, 'empty-config');
   const features = deduplicateFeatures(options?.features ?? []);