Fix otel async path

[l-trotta]

Closes #1268, making the structure of the otel output coherent between the sync and async path

[github-actions]

The backport to 8.19 failed:

The process '/usr/bin/git' failed with exit code 1

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add .worktrees/backport-8.19 8.19
# Navigate to the new working tree
cd .worktrees/backport-8.19
# Create a new branch
git switch --create backport-1269-to-8.19
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick --mainline 1 e81ebf4b03b88758dfa849fcb7932bc53a591aab
# Push it to GitHub
git push --set-upstream origin backport-1269-to-8.19
# Go back to the original working tree
cd ../..
# Delete the working tree
git worktree remove .worktrees/backport-8.19

Then, create a pull request where the base branch is 8.19 and the compare/head branch is backport-1269-to-8.19.