Bug 504047

SUMMARY
Spectacle fails to save screenshots if file name contains reserved characters on NTFS partitions with `windows_names` mount option. This usually happens when the window that is being captured has reserved characters in the title.
More info: https://learn.microsoft.com/en-us/windows/win32/fileio/naming-a-file#naming-conventions

STEPS TO REPRODUCE
1. Mount a NTFS partition with `windows_names` option.
2. Set screenshot save location to somewhere in the mounted NTFS partition.
3. Set filename template to something that contains `%T`.
4. Take a screenshot of a window that contains reserved characters.

OBSERVED RESULT
Two error dialogs with the following text:
1. QImageWriter cannot write image: Cannot open device for writing: Invalid argument
2. Cannot save screenshot. Error while writing file.

EXPECTED RESULT
Successfully saving screenshots with a normalized filename.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: 
KDE Plasma Version: 5.27.12
KDE Frameworks Version: 5.115.0
Qt Version: 5.15.13