Incorrect pipeline duration when it only has a single manual job

Summary

When a pipeline is passed the notification send to Slack displays incorrect time (00:00), see next:

The pipelines passed time displayed within GitLab is correct. So it is only related to the Slack notification.

Steps to reproduce

• Create a project on GitLab
• Enable Auto DevOps or create a .gitlab-ci.yml file that handles the ci/cd
• Enable Slack Integration for the project and enable the pipeline events
• Push a commit that triggers a pipeline
• When it fails it does show the pipeline time processing correct. If it succeeds it displays the time wrong.

Example Project

N/A

What is the current bug behavior?

Displaying incorrect time of the pipeline process time

What is the expected correct behavior?

Displaying the time correctly of the pipeline process time

Relevant logs and/or screenshots

N/A

Output of checks

This bug happens on GitLab.com

/label ~bug