rmcp_client: Add MCP elicitation support

What feature would you like to see?

For MCP tools that does modify operations, we put our tools behind an MCP Elicitation with a boolean request, to ensure we can have an explicit approval from the user of the client.

Inside https://github.com/openai/codex/blob/main/codex-rs/rmcp-client/src/logging_client_handler.rs#L38

what is done currently is Codex advertises that it has elicitation support, but it automatically declines the request, leading in an unexpected behavior.

Additional information

I see TODO (CODEX-3571): support elicitations.