Draft: Remove validate_core_schema

[sydney-runkle]

This improves perf significantly in pydantic, so we no longer have a use for this in pydantic-core.

cc @davidhewitt, before I continue:

• Can we remove the self schema gen
• Can I comb through tests using this function and either remove them or modify the schema errors?

[sydney-runkle]

Decided we don't need this in pydantic-core until we've decided skipping this step is stable.

[TyronMYoung11]

I dont know is related or not, but facing this error:

  File "\.venv\Lib\site-packages\pydantic\_internal\_core_utils.py", line 9, in <module>
    from pydantic_core import validate_core_schema as _validate_core_schema
ImportError: cannot import name 'validate_core_schema' from 'pydantic_core' (\.venv\Lib\site-packages\pydantic_core\__init__.py)

pydantic 2.11.7
pydantic_core 2.37.2