Files don't get saved on windows

The File Saver plugin failed to save on Windows, I recommend the FIleSaver plugin is replaced with a more robust solution

Start by reproducing the File Saver plugin failure on Windows and locating where the plugin is integrated into the Flutter drawing app. Compare the current saving behavior with the intended Windows behavior and determine whether a replacement is feasible. Done means files save successfully on Windows using the chosen robust solution.

Written by the indexing model from the issue text.