Allow customers to visually select a plan branch in the artifact downloader

Currently when selecting a plan to download an artifact from customers do not have a view of the plan branches. It appears that if the branch creates an artifact of the same name as the master (or another branch) the task downloads the most recent artifact.

Customers would like the ability to visually select the specific branch the artifact is pulled from in order to avoid any confusion/mistakes when downloading artifacts.

Currently the dropdown looks like this:

It would be great if each plan could possibly have a further dropdown showing its branches or even just making the plan branches searchable/useable in that list.