fix: custom favicon

[noscripter]

if favicon was uploaded and not stored in static upload folder, this logic is wrong, it should be used from Meta.config instead.

[barisusakli]

@noscripter what was the value stored in meta.config['brand:favicon']?

The code seems to always save the file at public/uploads/system/favicon.ico

[noscripter]

@barisusakli that's not the case when you use some plugins to override the uploadFavicon function found in ACP. Oh, I see, I've customized this function to response to the hook filter:uploadImage. Maybe this could be proposed to change too, I'll come up with these changes later for you to check out.🤝