More intuitive visual hint for nested runs

[dglazkov]

Just a number in a colored box might not be clear to the user. what other hints could there be?

[dglazkov]

@paullewis

Ok, ideas to play with:

• what if every component had an icon there, showing that it's successfully ran (or errored out).
• the icon is gray before the component ran
• for components that are composite, the icon is different and has a tiny count next to it, which goes away after it successfully finished (but maybe shows a number when errored out).
• the icon is clickable for composite components.

I am thinking that in the future, we'll use this same space for "Run Again" button?

Another slightly less baked idea... what if there was a tiny graph there somehow?

@donsbach obi wan