Child Pipelines with manual jobs are posted multiple times

[Blackclaws]

When running child pipelines with manual jobs, there are multiple posts for the child pipeline when the manual job is run. The message is the same as when the child pipeline is created the first time.

In general its questionable whether notifications for child pipelines (not to be confused with multi project pipelines) are desirable. Those don't even show up as individual pipelines in the pipeline view.

This gets much worse by the way on the success of a pipeline that has a lot of child pipelines. The channel will get swamped with: "Success for X" messages with all different pipelines shown one by one.