Console metric propagation shouldn't traverse non-injected metric ops

QUARKS-22 / PR-116 added "metric propagation" so edge segments get proper width rendering and edge hovers report metrics across injected ops.

The traversal code was including (non-injected) CounterOp and RateMetric oplets which is undesirable since each such oplet is included in the retrieved "counter metrics" hence each already ended up setting its adjecent edges' metric value. Hence traversing them too is unnecessary / extra work.