Correct the pipeline trigger time

Open Cindy Pallares 🦉 requested to merge cindy/gitlab-ce:pipeline-trigger-time into master

What does this MR do?

Correctly show the time the pipeline was triggered.

Why was this MR needed?

Currently when a pipeline is triggered the time stamp shows the time of the last commit, not when the pipeline was actually triggered.

Does this MR meet the acceptance criteria?

What are the relevant issue numbers?

#25240 (moved)