Include connector IDs in MCP tool call analytics (#32867)

## What changed

- Add the optional `connector_id` to `codex_mcp_tool_call_event` parameters.
- Populate it from the MCP tool call's `app_context` when available.

## Testing

- Extend the completed tool item analytics test to verify the connector ID is serialized.

GitOrigin-RevId: ea62202318dd492fa0ffd4ff1d48a66d1cc37e96

codex-rs/analytics/src/events.rs

@@ -674,6 +674,7 @@ pub(crate) struct CodexMcpToolCallEventParams {
     pub(crate) mcp_tool_name: String,
     pub(crate) mcp_error_present: bool,
     pub(crate) plugin_id: Option<String>,
+    pub(crate) connector_id: Option<String>,
 }
 
 #[derive(Serialize)]