fix: Fix "Unknown path" error when source user `files` folder has not been initialized

[Pytal]

Summary

Calling transfer() with a source user who has not yet logged in will throw an "Unknown path" error. To fix this we initialize the source user filesystem like we do with the destination user.

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• [ ] Tests (unit, integration, api and/or acceptance) are included
• [x] Screenshots before/after for front-end changes
• [x] Documentation (manuals or wiki) has been updated or is not required
• [ ] Backports requested where applicable (ex: critical bugfixes)