Pydantic issue

Pydantic 2.7 seems to be required.

When using SageMaker distribution 1.9, I get the following error installing sagemaker-core

```bash
!pip install --upgrade pip -q
!pip install sagemaker-core

->
ERROR: pip's dependency resolver does not currently take into account all the packages that are installed. This behaviour is the source of the following dependency conflicts.
gluonts 0.13.7 requires pydantic~=1.7, but you have pydantic 2.8.2 which is incompatible.
sagemaker-jupyterlab-extension-common 0.1.18 requires pydantic==1.*, but you have pydantic 2.8.2 which is incompatible.
```

Creating a training job, I get:
`TypeError: list_schema() got an unexpected keyword argument 'fail_fast'`

It seems I must first uninstall pydantic, then re-install pydantic==2.7.0 and then sagemaker-core, to get it working.

Start by reproducing the reported installation with SageMaker distribution 1.9 and the listed pip commands, then reproduce the training-job failure involving list_schema() and fail_fast. Trace the dependency requirements for sagemaker-core and the conflicting installed packages; done means the supported installation works without incompatible dependency errors and training-job creation no longer raises this TypeError.

Written by the indexing model from the issue text.