Cache Files updated based on API-Token's User

[tomcornall]

Theme cached files are being updated using the API token's User:

            // Find user settings for owner_id linked to API token used in request
            $userSettings = new UserSettings(User::find($token['owner_id']));
            $userTheme = $userSettings->get("edit_theme")['code'];

This is wrong, and was missed in testing. Instead, the theme should always be based on the lemonsync.json's "theme_code".