Pydantic deprecation warning: Support for class-based `config` is deprecated, use ConfigDict instead

[steffeng]

On import of BedrockAgentCoreApp a Pydantic deprecation warning occurs, e.g. during pytest runs. Besides noise, it is confusing since it is not clear if the issue is in application or Bedrock SDK code.

To Reproduce

1. open a python REPL
2. import BedrockAgentCoreApp

✗ python                                   
Python 3.13.11 (main, Dec  5 2025, 16:06:33) [Clang 17.0.0 (clang-1700.6.3.2)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
Cmd click to launch VS Code Native REPL
>>> import warnings
>>> warnings.simplefilter("always")
>>> from bedrock_agentcore import BedrockAgentCoreApp
[REDACTED]/.venv/lib/python3.13/site-packages/bedrock_agentcore/runtime/context.py:12: PydanticDeprecatedSince20: Support for class-based `config` is deprecated, use ConfigDict instead. Deprecated in Pydantic V2.0 to be removed in V3.0. See Pydantic V2 Migration Guide at https://errors.pydantic.dev/2.12/migration/
  class RequestContext(BaseModel):

Expected behavior
No deprecation warning.

Desktop (please complete the following information):

• OS: macOS
• Browser n/a
• Version 26.3

Additional context
bedrock-agentcore Version: 1.4.4
I'm using pydantic Version: 2.12.5, as required by bedrock-agentcore, mcp, pydantic-settings, strands-agents