The addition of the --unmeshed flag changed the rendering behavior of the
stat command so that resources with 0 meshed pods are not displayed by
default.

Rendering is based off the row's MeshedPodCount field which is currently not
set by func trafficSplitResourceQuery. This change sets that field now so
that in rendering, the trafficsplit resource is rendered in the output.

The reason for this not showing up in testing is addressed by #4272 where the
stat command behavior for no traffic is changed.

The following now works without --unmeshed flag being passed:

❯ bin/linkerd stat -A ts
NAMESPACE   NAME                    APEX          LEAF          WEIGHT   SUCCESS   RPS   LATENCY_P50   LATENCY_P95   LATENCY_P99
default     backend-traffic-split   backend-svc   backend-svc     500m         -     -             -             -             -
default     backend-traffic-split   backend-svc   failing-svc        0         -     -             -             -             -