Add log record when listening dag is partitioned but run has no key #59060
Description
Body
When the asset maneger fires an event, if a dag is listening to it but has no key, then it can't create the asset event, because it doesn't know what key to use.
Currently we just log an error to stdout.
But we should add a Log entry so that it can be seen in task logs.
Committer
- I acknowledge that I am a maintainer/committer of the Apache Airflow project.