update optimize-locales plugin types (#8087)

Author: stefanprobst

packages/dev/optimize-locales-plugin/LocalesPlugin.d.ts

@@ -4,5 +4,5 @@ type Options = {
   locales: readonly string[]
 };
 
-declare const plugin: UnpluginInstance<Options, boolean>;
+declare const plugin: UnpluginInstance<Options, false>;
 export = plugin;