When a build is queued the wrong duration is reported

On the Branch Summary page for a plan, there is a Branch Statistics section which shows a chart of the duration of recent builds, as well as the average duration. In the case where a build is queued, the time it is queued is included in the duration.

There are two key problems here. First, this is giving an inaccurate picture of whether the build time has changed significantly with a commit - in other words, I can't see if a commit significantly increased the build time. Secondly, it can throw off the average build time, which means the progress bar for running builds will be wrong.

In my case I've had builds queued when there was no elastic agent (because it died or because we shut it down) and the duration is then thrown way off. I've had average duration jump from 6 min to 13 min on a single build. I attached a screenshot.

The build duration should include only time spent actually building, not the time queued. Ideally the queued time would be reported separately, as requested in BAM-10938; however, that is a separate issue.