Implement adapter retry for Pydantic Validation Error

[TomeHirata]

This PR introduces RetryAdapter, which

1. Call the main_adapter.
2. Call the fallback_adapter if the main_adapter fails, c
3. Retry the main_adapter including previous response for max_retries times if fallback adapter failed.

Resolve #7693

Alternative design of adapter retry:

1. Implement the decorator method around the adapter call
   This design can separate the call function from the retry logic. However, faces difficulty in accessing the previous LLM call output.

2. Implement Retry as a dspy module
   This is the previous design before LiteLLM. However, Pydantic validation is a responsibility of adapter abstraction and having the retry logic in this layer should be cohesive.

3. Have the logic in BaseAdapter.call
   This approach is not suitable since several different adapters are used in the retry logic instead of retrying one adapter for multiple times.

[okhat]

Note to self: How does modifying the signature interact with demonstrations and with optimization?

[chenmoneygithub]

Nice work! Can we include some demo code + logging/screenshot on retry resolves the pydantic parsing error? Although I am almost sure that this is helpful for small models, I don't have a concrete idea on how robust this retry works.

[chenmoneygithub]

LGTM! Left two minor comments