The cached files aren't being removed after the stale duration is over!

## 🐛 The cached files aren't being removed after the stale duration is over!

With Custom Cache Manager, the stale duration isn't working! It's not removing the file after the stale duration is over. I had set the stale duration to 3 minutes, but the file was deleted even after more than 30 hours.

### Expected behavior
The cached files are supposed to be deleted after the stale duration of the file is over. But, the file continues to remain in the cache ruining the whole structure.

### Reproduction steps
Just cache a file with Custom Cache Manager, for DefaultCacheManager doesn't come with a stale duration option, and assign Stale Duration to anything, i assigned it 3 minutes to test it more efficiently. Then, I just invoked my function to see if the file is cached without displaying it, which I was doing with Cached_network_Image. I used the getFileFromCache function to get the file specifically and only from the cache, and it printed that the cached file exists, even after the day since is caching. Btw, remember I cached it for 3 minutes.

### Configuration

**Version:** flutter_cache_manager: ^3.3.1

**Platform:**
- [ ] :iphone: iOS
- [ ] :robot: Android

Tái hiện sự cố với Custom Cache Manager bằng cách sử dụng thời lượng stale là ba phút, sau đó gọi getFileFromCache khi thời lượng này đã trôi qua. Được xem là hoàn tất khi tệp được lưu trong cache bị xóa hoặc không còn được trả về từ cache; sự cố không nêu tên tệp nguồn hoặc bài kiểm thử cần kiểm tra.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.