[codex][otel] propagate user email in otel events (#5223)

include user email into otel events for proper user-level attribution in
case of workspace setup

codex-rs/core/src/client.rs

@@ -1030,6 +1030,7 @@ mod tests {
             "test",
             "test",
             None,
+            Some("test@test.com".to_string()),
             Some(AuthMode::ChatGPT),
             false,
             "test".to_string(),