Close discarded raw responses in high-level void methods

[fallintoplace]

Summary

• explicitly close raw responses in high-level blocking void methods for container delete, response delete, container file delete, and realtime call accept/hangup/refer/reject
• explicitly close raw responses in the matching async void methods instead of discarding them with empty thenAccept {} callbacks
• add a focused unit test that verifies each affected blocking and async method closes a successful raw response exactly once

Why

These high-level methods delegate to raw-response methods that return lazily parsed parseable wrappers. For successful empty-body endpoints, discarding that wrapper without parsing or closing it can leave the underlying response open.

Validation

• env JAVA_HOME=/opt/homebrew/opt/openjdk@21/libexec/openjdk.jdk/Contents/Home PATH=/opt/homebrew/opt/openjdk@21/libexec/openjdk.jdk/Contents/Home/bin:$PATH ./gradlew :openai-java-core:test --tests com.openai.services.HighLevelUnitMethodsCloseResponseTest
• env JAVA_HOME=/opt/homebrew/opt/openjdk@21/libexec/openjdk.jdk/Contents/Home PATH=/opt/homebrew/opt/openjdk@21/libexec/openjdk.jdk/Contents/Home/bin:$PATH ./gradlew :openai-java-core:lintKotlin

Notes

• The generated service integration tests for these endpoints use TestServerExtension and require the repo mock server (./scripts/mock), which was not running in this environment.