burrow 1.0 reports only one consumer while two consumers are active

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I am migrating to burrow 1.0 our configuration and I've noticed that I have only one consumer available:

```
[kkrzyzaniak@kafka01:~]$ curl --silent http://localhost:8000/v3/kafka/central/consumer
{
"error": false,
"message": "consumer list returned",
"consumers": [
"logstash-turbo"
],
"request": {
"url": "/v3/kafka/central/consumer",
"host": "kafka01"
}
}
```

While there are two active consumers:

```
[kkrzyzaniak@kafka01:~]$ /opt/kafka/bin/kafka-consumer-groups.sh --bootstrap-server localhost:9092 --list
Note: This will only show information about consumers that use the Java consumer API (non-ZooKeeper-based consumers).

logstash
logstash-turbo
```

My config:

```
[general]
pidfile="/run/burrow/burrow.pid"
stdout-logfile="/var/log/burrow/burrow.out"
access-control-allow-origin=""

[logging]
filename="/var/log/burrow/burrow.log"
level="info"
maxsize=100
maxbackups=30
maxage=10
use-localtime=false
use-compression=true

[zookeeper]
servers=[ "zk01:2181", "zk02:2181", "zk03:2181" ]
timeout=6
root-path="/burrow"

[client-profile.test]
client-id="burrow-test"
kafka-version="0.10.0"

[cluster.central]
class-name="kafka"
servers=[ "kafka01:9092", "kafka02:9092", "kafka03:9092" ]
client-profile="test"
topic-refresh=120
offset-refresh=30

[consumer.central]
class-name="kafka"
cluster="central"
servers=[ "kafka01:9092", "kafka02:9092", "kafka03:9092" ]
client-profile="test"
group-blacklist=""
group-whitelist=""

[httpserver.default]
address=":8000"

[storage.default]
class-name="inmemory"
workers=20
intervals=15
expire-group=604800
min-distance=1
```

Start at the /v3/kafka/central/consumer endpoint and compare its consumer list with the kafka-consumer-groups.sh --list output shown in the report. Trace how the central consumer configuration discovers groups, then verify that both logstash and logstash-turbo appear in the endpoint response.

Written by the indexing model from the issue text.