[Question] set-bookie-affinity-group don't work

#### Expected behavior

3 bookies
```
{
"bookies" : [ {
"bookieId" : "7.32.133.237:3181"
}, {
"bookieId" : "7.32.133.235:3181"
}, {
"bookieId" : "7.32.133.236:3181"
} ]
}

```

1 topic with 2 partition

./bin/pulsar-admin bookies set-bookie-rack -b 7.32.133.235:3181 -r rack1 -g group1
./bin/pulsar-admin bookies set-bookie-rack -b 7.32.133.236:3181 -r rack1 -g group1
./bin/pulsar-admin namespaces set-bookie-affinity-group zcola_qos/test --primary-group group1
./bin/pulsar-admin namespaces unload zcola_qos/test

Disk IO should happen on 7.32.133.235:3181 and 7.32.133.236:3181， 7.32.133.237:3181 is zero io

#### Actual behavior

Disk IO happens at 7.32.133.236:3181 and 7.32.133.237:3181, 7.32.133.235:3181 is zero io
#### Steps to reproduce

How can we reproduce the issue

#### System configuration
**Pulsar version**: 2.9.2

Start with the pulsar-admin bookies set-bookie-rack and namespaces set-bookie-affinity-group commands, then inspect the unload behavior described for Pulsar 2.9.2. Reproduce the two-partition setup and compare disk IO across the three listed bookies; done means the configured primary group receives the expected IO distribution.

Written by the indexing model from the issue text.