fix(general): some fixes and improvements of Play visibility (#14384)

* fix(backend): missing `visibility` param in packing flash

* fix(frontend): use `visibility` value got from API

* enhance(frontend): change preview appearance of private Play

* Update CHANGELOG.md

packages/misskey-js/src/autogen/types.ts

@@ -4672,6 +4672,8 @@ export type components = {
       title: string;
       summary: string;
       script: string;
+      /** @enum {string} */
+      visibility: 'private' | 'public';
       likedCount: number | null;
       isLiked?: boolean;
     };