Flaky test: NettyHttpServerConnectionDrainTest

https://github.com/apple/servicetalk/actions/runs/20862469417/job/59945346507?pr=3390

```
> Task :servicetalk-http-netty:test

NettyHttpServerConnectionDrainTest > requestIsAutoDrainedWhenUserFailsToConsumeAndResponseBodyFails() FAILED
org.opentest4j.AssertionFailedError: expected: but was:
at app//org.junit.jupiter.api.AssertionFailureBuilder.build(AssertionFailureBuilder.java:151)
at app//org.junit.jupiter.api.AssertionFailureBuilder.buildAndThrow(AssertionFailureBuilder.java:132)
at app//org.junit.jupiter.api.AssertTrue.failNotTrue(AssertTrue.java:63)
at app//org.junit.jupiter.api.AssertTrue.assertTrue(AssertTrue.java:36)
at app//org.junit.jupiter.api.AssertTrue.assertTrue(AssertTrue.java:31)
at app//org.junit.jupiter.api.Assertions.assertTrue(Assertions.java:183)
```

Start with the linked CI run and the NettyHttpServerConnectionDrainTest failure, especially requestIsAutoDrainedWhenUserFailsToConsumeAndResponseBodyFails(). Run the :servicetalk-http-netty:test task to reproduce it; done means the test reliably passes and the reported assertion failure is resolved.

Written by the indexing model from the issue text.