fix: Close based on whether connection is active, not status variable (…

…#1750)

google-cloud-bigquerystorage/src/main/java/com/google/cloud/bigquery/storage/v1/StreamWriter.java

@@ -538,7 +538,7 @@ private void waitForDoneCallback(long duration, TimeUnit timeUnit) {
     while (System.nanoTime() <= deadline) {
       this.lock.lock();
       try {
-        if (connectionFinalStatus != null) {
+        if (!this.streamConnectionIsConnected) {
           // Done callback is received, return.
           return;
         }