[Bug] DefaultReceiptHandleManager#clientIsOffline The method should check Channel.isActive() to avoid resource leaks.

### Before Creating the Bug Report

- [x] I found a bug, not just asking a question, which should be created in [GitHub Discussions](https://github.com/apache/rocketmq/discussions).

- [x] I have searched the [GitHub Issues](https://github.com/apache/rocketmq/issues) and [GitHub Discussions](https://github.com/apache/rocketmq/discussions) of this repository and believe that this is not a duplicate.

- [x] I have confirmed that this bug belongs to the current repository, not other repositories of RocketMQ.

### Runtime platform environment

DefaultReceiptHandleManager#clientIsOffline The method should check Channel.isActive() to avoid resource leaks.

### RocketMQ version

all 5.x versions

### JDK Version

_No response_

### Describe the Bug

clientIsOffline The method should check Channel.isActive() to avoid resource leaks.

### Steps to Reproduce

DefaultReceiptHandleManager#clientIsOffline The method should check Channel.isActive() to avoid resource leaks.

### What Did You Expect to See?

DefaultReceiptHandleManager#clientIsOffline The method should check Channel.isActive() to avoid resource leaks.

### What Did You See Instead?

DefaultReceiptHandleManager#clientIsOffline The method should check Channel.isActive() to avoid resource leaks.

### Additional Context

_No response_

Start at DefaultReceiptHandleManager#clientIsOffline and inspect how the client channel state is evaluated. Confirm how Channel.isActive() should affect offline detection and resource cleanup, then verify that the behavior no longer permits the reported resource leak.

Written by the indexing model from the issue text.