Migrations: Update migration notebook to use linkml's validator instead of jsonschema's validator

[eecavanna]

In this notebook:

• demo/metadata_migration/notebooks/migrate_10_9_1_to_11_0_0.ipynb

...use this:

• https://linkml.io/linkml/data/validating-data.html

...instead of this:

• https://python-jsonschema.readthedocs.io/en/stable/api/jsonschema/validators/#jsonschema.validators.Draft201909Validator