Confusing error message if $HOME/.config is missing

[ssokolow]

Describe the bug
If ~/.config is missing, then SMAPI errors out when trying to create the logs folder with a spurious message about the Stardew Valley game binary already existing.

To Reproduce
Exact steps which reproduce the bug, if possible. For example:

1. Take a working SMAPI setup in a firejail sandbox which uses the private directive to give it its own private $HOME
2. Set up a new copy which uses the same SMAPI install but a different private path that's starting out empty. (I do cp -r /path/to/stardew/valley /path/to/new/copy/for/different/mods and then re-run my home-made sandboxify script to regenerate the firejail profile and launcher with the new paths)
3. Run Stardew Valley
4. Because the private $HOME hasn't had a $HOME/.config created yet and SMAPI doesn't use the C# equivalent to mkdir's --parents option, SMAPI errors out and, does so with a very misleading error message.

I've confirmed that running mkdir <path to firejail-provided private $HOME>/.config allows SMAPI to launch successfully.

Log file
Can't upload the SMAPI log because the confusing error is SMAPI failing to create ~/.config/StardewValley/ErrorLogs.

Screenshots