Remove duplicate method instrumentation

[sambostock]

This removes duplicate calls to add_instrumentation_data(method: ...).

Motivation and Context

handle_request already adds the method to the instrumentation data, so there is no need to repeat this. Moreover, consumers can override these anyway.

How Has This Been Tested?

This is covered by existing tests.

Breaking Changes

Types of changes

There is no visible change, just a reduction in duplicate work.

Checklist

• I have read the MCP Documentation
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling N/A
• I have added or updated documentation as needed N/A

Additional context

I left behind some calls to add_instrumentation_data which could have been moved.

def read_resource_no_content(request)
  add_instrumentation_data(resource_uri: request[:uri])
  []
end

I wasn't sure if we wanted all reads to unconditionally instrument the URI.

def call_tool(request)
  tool_name = request[:name]
  tool = tools[tool_name]
  unless tool
    add_instrumentation_data(error: :tool_not_found)
    raise RequestHandlerError.new("Tool not found #{tool_name}", request, error_type: :tool_not_found)
  end

  arguments = request[:arguments]
  add_instrumentation_data(tool_name:)

  # ...
end

I wasn't sure if we wanted to unconditionally instrument the tool_name, or only instrument known tools (as we do now).

def get_prompt(request)
  prompt_name = request[:name]
  prompt = @prompts[prompt_name]
  unless prompt
    add_instrumentation_data(error: :prompt_not_found)
    raise RequestHandlerError.new("Prompt not found #{prompt_name}", request, error_type: :prompt_not_found)
  end

  add_instrumentation_data(prompt_name:)

  # ...
end

Likewise, I wasn't sure if we only want to instrument known prompts.

[koic]

I think it's reasonable to remove these calls to add_instrumentation_data, as they are redundant.