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

使用三分钟的过期时长复现 Custom Cache Manager 的问题，然后在该时长经过后调用 getFileFromCache。缓存的文件被移除或不再从缓存中返回即表示完成；该问题未指定要检查的源文件或测试。

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