[elicitations] Switch to use MCP style elicitation payload for mcp tool approvals. (#13621)

- [x] Switch to use MCP style elicitation payload for mcp tool
approvals.
- [ ] TODO: Update the UI to support the full spec.

codex-rs/exec/src/lib.rs

@@ -692,6 +692,7 @@ async fn run_exec_session(args: ExecRunArgs) -> anyhow::Result<()> {
                     request_id: ev.id.clone(),
                     decision: ElicitationAction::Cancel,
                     content: None,
+                    meta: None,
                 })
                 .await?;
         }