Relocate stream.close() to onResponseComplete

runtime/protocol/http-client-engines/http-client-engine-crt/jvm/src/aws/smithy/kotlin/runtime/http/engine/crt/SdkStreamResponseHandler.kt

@@ -166,7 +166,7 @@ internal class SdkStreamResponseHandler(
         // stream is only valid until the end of this callback, ensure any further data being read downstream
         // doesn't call incrementWindow on a resource that has been free'd
         lock.withLock {
-            crtStream?.close() ?: throw IllegalStateException("onResponseComplete expected CRT HttpStream to be non-null")
+            crtStream?.close()
             crtStream = null
             streamCompleted = true
         }