The metric resolved the Kinetics-400 label file via a wm-eval-era
``_third_party/umt/kinetics_400_categories.txt`` path that no longer
exists after the vbench-as-submodule port. ``os.path.exists`` was
silently False, leaving the label dict empty; every prediction then
mapped to the empty string and every score returned 0.0.
Resolve the path through ``vbench.third_party.umt.__file__`` instead,
which always points at the pinned upstream submodule.
shaoxiongduan
8f5ebe2aeb