Clicked actors on production tab should use clicked state

[Dzierzan]

I would be great if a clicked actor on production tab was using icon-clicked state.

[IceReaper]

It lies within the production palette code. It does not support -highlighted or such suffixes. Only the clock to be rendered on top. Thats not a big issue, but requires a PR on OpenRA itself. Other solution: (let) Write your own sidebar. It pretty simplistic anyway.