fix(mcp+anthropic): vanilla mcp crashed due to argument manipulation

[nirga]

• [ ] I have added tests that cover my changes.
• [ ] If adding a new instrumentation or changing an existing one, I've added screenshots from some observability platform showing the change.
• [ ] PR name follows conventional commits format: feat(instrumentation): ... or fix(instrumentation): ....
• [ ] (If applicable) I have updated the documentation accordingly.

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[!IMPORTANT] Fixes MCP client crash by adjusting argument handling and adds an MCP-Anthropic integration example.

• Behavior:
  • Fixes crash in MCP client by modifying traced_method in instrumentation.py to handle arguments correctly.
  • Adds mcp_sonnet_example.py to demonstrate MCP client usage with Anthropic integration.
• Serialization:
  • Introduces JSONEncoder in utils.py to handle objects with to_json or model_dump_json methods.
• Dependencies:
  • Updates pyproject.toml to include mcp version ^1.7.1.

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