chore: remove duplicate AnthropicProviderDataValidator (#3512)

# What does this PR do?

removes the duplicate AnthropicProviderDataValidator

the active one is in config.py

## Test Plan

ci

Author: mattf

llama_stack/providers/remote/inference/anthropic/__init__.py

@@ -4,15 +4,9 @@
 # This source code is licensed under the terms described in the LICENSE file in
 # the root directory of this source tree.
 
-from pydantic import BaseModel
-
 from .config import AnthropicConfig
 
 
-class AnthropicProviderDataValidator(BaseModel):
-    anthropic_api_key: str | None = None
-
-
 async def get_adapter_impl(config: AnthropicConfig, _deps):
     from .anthropic import AnthropicInferenceAdapter