The ServiceX Dashboard does not clear out transforms stuck in "lookup"

[gordonwatts]

When ServiceX has trouble with a very long lookup, sometimes transforms get stuck in the lookup phase. The old transforms continue
to be sorted to the top of the dashboard when that happens, and if enough of them occur, they will remain there, clogging up the top of
the display with old transforms.

• Transforms that die in the lookup phase should be killed (somehow).