Fix negative timestamps when using secretsdump local on windows

[NeffIsBack]

When using secrestdump SAM dump on Windows (e.g. --sam secdump or the backup_operator module) secretsdump crashes. This is due to the negative timestamp that is passed into datetime which can't be handled on windows:

# On Windows localtime_s throws an OSError for negative values,
# thus we can't perform fold detection for values of time less
# than the max time fold. See comments in _datetimemodule's
# version of this method for more details.
if t < max_fold_seconds and sys.platform.startswith("win"):
return result

This happens when the userAccountF['LastIncorrectPasswordTimestamp'] is zero in nt time and is then converted to a negative unixTimestamp integer. This can easily be fixed by manually returning the 0 nt timestamp on when the input is 0.

Before:

After: