fix: correct the widget definition type (#76)

Author: e0ipso

types/WidgetDefinition.d.ts

@@ -5,7 +5,10 @@ export type WidgetMetadataBasic = {
   title: string;
   status?: 'stable' | 'beta' | 'wip' | 'deprecated';
   settingsSchema?: {
-    fields: Schema;
+    type: 'object';
+    properties: {
+      fields: Schema;
+    };
   };
   description?: string;
   additionalCustomProperties?: Record<string, scalar>;