moonbase/stores: Use boolean shorthand when writing config

packages/core-extensions/src/moonbase/webpackModules/stores.ts

···
     let val = this.config.extensions[ext.id];
 
     if (val == null) {
-      this.config.extensions[ext.id] = { enabled };
+      this.config.extensions[ext.id] = enabled;
       this.modified = this.isModified();
       this.emitChange();
       return;