pimd: Include pruneTx/pruneRx for `show ip pim interface traffic WORD json`

pimd: Include pruneTx/pruneRx for `show ip pim interface traffic WORD json`

```
exit1-debian-11# sh ip pim interface traffic eth2 json
{
  "eth2":{
    "name":"eth2",
    "state":"up",
    "address":"192.168.10.123",
    "index":4,
    "flagMulticast":true,
    "flagBroadcast":true,
    "lanDelayEnabled":true,
    "helloRx":2,
    "helloTx":2,
    "joinRx":0,
    "joinTx":1,
    "pruneRx":0,
    "pruneTx":0,
    "registerRx":0,
    "registerTx":0,
    "registerStopRx":0,
    "registerStopTx":0,
    "assertRx":0,
    "assertTx":0,
    "bsmRx":0,
    "bsmTx":0
  }
}
```

Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>