ModelFilePath within a .mbconfig file stores an absolute path, which prevents the project to work correctly if moved or cloned.

**System Information (please complete the following information):**
- Windows 10
- ML.NET v3.0.1
- NET 8.0

**Describe the bug**

At the end of a training run using the ML wizard, a .mbconfig file is created.

That file contains an entry called "ModelFilePath:" which points to the .mlnet file, which happens to be in the same directory as the .mbconfig file.

But, I've noticed that "ModelFilePath:" holds the full, absolute file path to the model, instead of just the file name, or the relative path name.

This can cause trouble if the project is moved to another directory, or it is cloned in another machine.

**To Reproduce**

Just do some training using the wizard, and check the "ModelFilePath:" entry inside the .mbconfig and check whether it's an absolute or a relative path.

**Expected behavior**

"ModelFilePath:" should not be an absolute path.