"Set as available offline" is cleared when clearing cache ios app

Is your feature request related to a problem? Please describe.
the clear cache option clears everything. Which I understand is it's purpose, but having the option to still maintain "set as offline" files available would be nice rather than re downloading them. The Problem is that viewing images and other files downloads them to your device quickly filling up phone/device space and requiring you to clear the cache. (To put it all simply when clearing the cache please do not clear the favorites if the option is to have them available offline or clear the files that are set to available offline)

Describe the solution you'd like
Set files as available offline should remain available even after clearing the cache

Describe alternatives you've considered
There is the option to have "favorites available offline" but that too is cleared when clearing the cache. the other thing is that even if over a network not on wifi it will continue to re download the files to your device with no option to choose otherwise.

Additional context
Great app, just some minor tweaks that I think can make it even better.

The issue names no files or tests. Start by reproducing cache clearing with files marked available offline, then trace the clear-cache and offline-availability handling in the iOS app; done means clearing temporary cache data preserves those offline files and does not require them to be downloaded again.