HF RL Explorer

Issue: grpclb PICK FIRST mode should delegate to a child pick first LoadBalancer

Issue: grpclb PICK FIRST mode should delegate to a child pick first LoadBalancer: a task in LegoFlow-SWE (Harbor dataset). The grpclb state’s picker must be updated to use the child’s picker via the ChildLbPickerEntry when in PICK FIRST mode. The child policy’s connectivity state (e.g., CONNECTING…

The task

The `grpclb` state’s picker must be updated to use the child’s picker via the `ChildLbPickerEntry` when in `PICK_FIRST` mode. The child policy’s connectivity state (e.g., `CONNECTING` initially) should be reflected in the `grpclb` state’s picker through `updateBalancingState`.

Part of Lego-X/LegoFlow-SWE.