Display stages in valid order in stages dropdown on build page

Currently stages in stages dropdown on builds page are not in valid order. It may be important to display stages in other those are defined in the pipeline.

/cc @markpundsack @ayufan @annabeldunstone

Yes, let's try to get this sorted in 8.11.

Milestone changed to %8.12

Reassigned to @ayufan

Mentioned in merge request !6430 (merged)

Status changed to closed by merge request !6430 (merged)

Mentioned in commit a4e24cd6

mentioned in merge request !14785