fix: set default roles for keyrings to include 'admin'

- Updated the default value for the roles property in the Keyrings schema to ensure 'admin' is included by default.

Author: tacxou

apps/api/src/core/keyrings/_schemas/keyrings.schema.ts

@@ -26,7 +26,7 @@ export class Keyrings extends AbstractSchema {
 
   @Prop({
     type: [String],
-    default: [],
+    default: ['admin'],
   })
   public roles?: string[];