1982058 - Surface `tier 2` tasks more subtly in the UI

Status: NEW

(Tree Management :: Treeherder, enhancement)

Description

[Andrew Halberstadt [:ahal]]

Currently when a task is defined as tier 2, we create a whole new group for it. For example, if we have a tier 1 python test as well as a tier 2 python test, Treeherder will display something like:

py3(mach) py3[tier-2](mozbuild)

This adds a lot of visual clutter, making Treeherder feel more overwhelming than it needs to. The primary use case of having tier-2, is for sheriffs to tell whether a failure should cause a backout or not. I'm open to suggestions, but personally I don't think it needs to be part of the Treeherder symbol at all.

Instead of having the tier be part of the group, I propose we display the tier prominently in the "Task Info" pane (bottom left when you click a task). Sheriffs can then either look there, or use the existing tier filters to determine which failures are tier 1 vs tier 2.

If it's important that we still make it easy to tell which failures are tier 2 at a glance (which I'm not convinced it should be), maybe we can make tier 2 failures a slightly different colour from tier 1 failures, like a lighter shade of orange or something. Though this might make the UI more overwhelming in a different way.. so I'm unsure if this colour thing is a good idea.