Extract to own method, fix wrong return type
Extract to own method, fix wrong return type

This part of getTaskHealthMessage was a bit unwieldy and deserved to be
moved outside of the switch. Also, it was returning an array of strings
rather than a joined string, which is fixed in this commit.

watonyweng/marathon-ui,Raffo/marathon-ui,Raffo/marathon-ui,yp-engineering/marathon-ui,mesosphere/marathon-ui,watonyweng/marathon-ui,mesosphere/marathon-ui,cribalik/marathon-ui,cribalik/marathon-ui,janisz/marathon-ui,quamilek/marathon-ui,yp-engineering/marathon-ui,Kosta-Github/marathon-ui,janisz/marathon-ui,Kosta-Github/marathon-ui,quamilek/marathon-ui