Python: [BREAKING] Remove FunctionTool[Any] compatibility shim for schema passthrough (#3600) (#3907)

* Fix #3600: Pass JSON schemas through without Pydantic conversion

This change optimizes FunctionTool and MCP flows by passing JSON schemas
directly to providers without converting them to Pydantic models first.

Key changes:
- Store JSON schema as-is when supplied to FunctionTool
- Skip Pydantic model_validate for schema-supplied tools in invoke()
- Return MCP tool schemas directly without conversion
- Add comprehensive tests for schema passthrough behavior

Performance benefits:
- Eliminates expensive Pydantic model creation for supplied schemas
- Preserves exact schema structure (additionalProperties, custom fields, etc.)
- Reduces memory overhead and initialization time

Maintains backward compatibility:
- Function signature inference still uses Pydantic models
- Explicit Pydantic models passed as input_model work as before
- All existing tests pass

* Fix schema passthrough validation and remove helper

* Simplify FunctionTool without generic model dependency

* Fix FunctionTool typing fallout in 3600

* Remove FunctionTool[Any] compatibility shim

* Use serializable kwargs in OTEL tool args

python/packages/claude/agent_framework_claude/_agent.py

@@ -484,7 +484,7 @@ class ClaudeAgent(BaseAgent, Generic[OptionsT]):
 
         return create_sdk_mcp_server(name=TOOLS_MCP_SERVER_NAME, tools=sdk_tools), tool_names
 
-    def _function_tool_to_sdk_mcp_tool(self, func_tool: FunctionTool[Any]) -> SdkMcpTool[Any]:
+    def _function_tool_to_sdk_mcp_tool(self, func_tool: FunctionTool) -> SdkMcpTool[Any]:
         """Convert a FunctionTool to an SDK MCP tool.
 
         Args: