[Tech] Resolve baseUrl in tests

[CommandMC]

Originally part of #2176

Jest now knows about our baseUrl, making imports from backend/.../common/... possible. Nothing groundbreaking, just a nice-to-have when writing tests

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Use the following Checklist if you have changed something on the Backend or Frontend:

• Tested the feature and it's working on a current and clean install.
• Tested the main App features and they are still working on a current and clean install. (Login, Install, Play, Uninstall, Move games, etc.)
• Created / Updated Tests (If necessary)
• Created / Updated documentation (If necessary)

[Nocccer]

LGTM. I wonder if the test do not complain anymore for none test files. I had alot of situation where the test said it could not import backend/utils.ts in main.ts for example.

[CommandMC]

I wonder if the test do not complain anymore for none test files

Yup, that's also now resolved. Since you mentioned it, I've also gone over those files and removed some more redundant relative paths

[Nocccer]

I wonder if the test do not complain anymore for none test files

Yup, that's also now resolved. Since you mentioned it, I've also gone over those files and removed some more redundant relative paths

Looked over it. I can't approve twice :D