pydantic-evals should optionally raise an exception if some or all cases raise an exception

[samuelcolvin]

Initial Checks

• I confirm that I'm using the latest version of Pydantic AI
• I confirm that I searched for my issue in https://github.com/pydantic/pydantic-ai/issues before opening this issue

Description

New flag on evaluate(errors: literal['raise-if-any', 'raise-if-all', 'never-raise'] = 'never-raise')

cc @dmontagu

Example Code

Python, Pydantic AI & LLM client version

1.0.6