Describe the bug

When the action is run with comment-pr: on-diff, it works as intended when ran with command: plan: comments are only added if the plan contains changes, and if a commit is pushed that causes a re-run to plan "No changes", then the comment is removed again.

Unfortunately it has a slightly problematic behavior when ran with command: apply. In that case you'd expect the comment to be updated to "Applied ..." if it exists, just like it is without comment-pr: on-diff, but the comment is instead deleted entirely. This makes it difficult to evaluate what infrastructure changes were actually applied at a later time.

I believe this behavior happens because terraform apply outputs an exit code of 0 when it succeeds. This causes this code to delete the comment instead of updating it:

To Reproduce

1. Run the action with command: plan and comment-pr: on-diff for a PR with changes.
2. Observe that a comment is added to the PR
3. Run the action with command: apply and comment-pr: on-diff for that same PR.
4. Observe that the comment is deleted.

Expected behavior

The comment is updated to reflect that it has been applied, but is not deleted.