### FIXES + MINOR IMPROVEMENTS:
- Fixed issue18685: Not a real issue. PR18648 added some logging that made
evident a missing check on the validity of the paths in `games.yml`
before trying to manage the path as a possible ISO file. That missing
check was already present but simply invisible due to missing log
- Fixed `bytes_to_hex()` function used to store file hash hex string: In
some cases the integrity check wrongly reported the check as failed
- Optimized `fs::get_optical_raw_device()` function: Moved under
`_WIN32` block a check valid only on `Windows` and simplified the logic
to detect a CDROM / BD as raw device
- Used `iso_file` objects instead of `fs:file` in `ISO.cpp`: It allows
to use proper `bool()` operator on some checks