[Bug] when deploy in ipv6,HeartbeatNamespace will failed when check

### Search before asking

- [X] I searched in the [issues](https://github.com/apache/pulsar/issues) and found nothing similar.

### Version

2.7 and master

### Minimal reproduce step

just run in ipv6

### What did you expect to see?

start ok

### What did you see instead?

failed

```
16:42:01.444 [main] ERROR org.apache.pulsar.PulsarBrokerStarter - Failed to start pulsar service.
org.apache.pulsar.broker.PulsarServerException: org.apache.pulsar.broker.PulsarServerException: java.lang.IllegalArgumentException: Invalid named entity: [fe80::5054:ff:fe69:741c]:8080
at org.apache.pulsar.broker.PulsarService.start(PulsarService.java:651) ~[pulsar-broker.jar:2.7.2]
at org.apache.pulsar.PulsarBrokerStarter$BrokerStarter.start(PulsarBrokerStarter.java:281) ~[pulsar-broker.jar:2.7.2]
at org.apache.pulsar.PulsarBrokerStarter.main(PulsarBrokerStarter.java:350) [pulsar-broker.jar:2.7.2]
Caused by: org.apache.pulsar.broker.PulsarServerException: java.lang.IllegalArgumentException: Invalid named entity: [fe80::5054:ff:fe69:741c]:8080
at org.apache.pulsar.broker.namespace.NamespaceService.registerNamespace(NamespaceService.java:361) ~[pulsar-broker.jar:2.7.2]
at org.apache.pulsar.broker.namespace.NamespaceService.registerBootstrapNamespaces(NamespaceService.java:303) ~[pulsar-broker.jar:2.7.2]
at org.apache.pulsar.broker.PulsarService.start(PulsarService.java:602) ~[pulsar-broker.jar:2.7.2]
... 2 more
Caused by: java.lang.IllegalArgumentException: Invalid named entity: [fe80::5054:ff:fe69:741c]:8080
at org.apache.pulsar.common.naming.NamedEntity.checkName(NamedEntity.java:39) ~[org.apache.pulsar-pulsar-common-2.7.2.jar:2.7.2]
at org.apache.pulsar.common.naming.NamespaceName.validateNamespaceName(NamespaceName.java:197) ~[org.apache.pulsar-pulsar-common-2.7.2.jar:2.7.2]
at org.apache.pulsar.common.naming.NamespaceName.(NamespaceName.java:98) ~[org.apache.pulsar-pulsar-common-2.7.2.jar:2.7.2]
at org.apache.pulsar.common.naming.NamespaceName.(NamespaceName.java:34) ~[org.apache.pulsar-pulsar-common-2.7.2.jar:2.7.2]
at org.apache.pulsar.common.naming.NamespaceName$1.load(NamespaceName.java:46) ~[org.apache.pulsar-pulsar-common-2.7.2.jar:2.7.2]
at org.apache.pulsar.common.naming.NamespaceName$1.load(NamespaceName.java:43) ~[org.apache.pulsar-pulsar-common-2.7.2.jar:2.7.2]
at com.google.common.cache.LocalCache$LoadingValueReference.loadFuture(LocalCache.java:3529) ~[com.google.guava-guava-30.1-jre.jar:?]
at com.google.common.cache.LocalCache$Segment.loadSync(LocalCache.java:2278) ~[com.google.guava-guava-30.1-jre.jar:?]
at com.google.common.cache.LocalCache$Segment.lockedGetOrLoad(LocalCache.java:2155) ~[com.google.guava-guava-30.1-jre.jar:?]
at com.google.common.cache.LocalCache$Segment.get(LocalCache.java:2045) ~[com.google.guava-guava-30.1-jre.jar:?]
at com.google.common.cache.LocalCache.get(LocalCache.java:3951) ~[com.google.guava-guava-30.1-jre.jar:?]
at com.google.common.cache.LocalCache.getOrLoad(LocalCache.java:3974) ~[com.google.guava-guava-30.1-jre.jar:?]
at com.google.common.cache.LocalCache$LocalLoadingCache.get(LocalCache.java:4935) ~[com.google.guava-guava-30.1-jre.jar:?]
at org.apache.pulsar.common.naming.NamespaceName.get(NamespaceName.java:69) ~[org.apache.pulsar-pulsar-common-2.7.2.jar:2.7.2]
at org.apache.pulsar.broker.namespace.NamespaceService.registerNamespace(NamespaceService.java:330) ~[pulsar-broker.jar:2.7.2]
at org.apache.pulsar.broker.namespace.NamespaceService.registerBootstrapNamespaces(NamespaceService.java:303) ~[pulsar-broker.jar:2.7.2]
at org.apache.pulsar.broker.PulsarService.start(PulsarService.java:602) ~[pulsar-broker.jar:2.7.2]
... 2 more

```

### Anything else?

because we use host as namespace ,but host has "[]" in ipv6 ,will fail when check in NamedEntity

### Are you willing to submit a PR?

- [X] I'm willing to submit a PR!

Reproduce the startup failure in an IPv6 environment, then trace the stack from NamespaceService.registerNamespace through NamespaceName and NamedEntity.checkName. Check how the bracketed IPv6 host is passed as a namespace name; done means the broker starts successfully and the heartbeat namespace registers without the Invalid named entity error.

Written by the indexing model from the issue text.