issue with the stalePeriod config

I’ve encountered an issue with the stalePeriod setting in our CustomCacheManager when using it with cached_network_image. I tried setting different values, such as 1 minute, 1 day, and 15 days, but it doesn’t seem to take effect.

Here’s the current implementation:

```

class CustomCacheManager {
static const key = 'customCacheKey';
static CacheManager instance = CacheManager(
Config(
key,
stalePeriod: const Duration(days: 15),
),
);
}

```

I expected the cache to expire based on the stalePeriod value, but the images are still being loaded from cache beyond the set duration. Are there any limitations or additional configurations required for cached_network_image to respect this setting?

Would appreciate any insights. Thanks!

cached_network_image: ^3.4.1
flutter_cache_manager: ^3.4.1
flutter: 3.29.2