Remove installation of metafacture-fix from Dockerfile

[Phu2]

As metafacture-fix is now included in metafacture-core we can skip this installation step.

See

• https://github.com/metafacture/metafacture-playground/blob/main/Dockerfile.dev#L39
• https://github.com/metafacture/metafacture-playground/blob/main/Dockerfile.prod#L39