[FLINK-37611] Deflake KafkaWriterFaultToleranceITCase.testWriteExceptionWhenKafkaUnavailable

Apparently, with newer kafka-clients library, we may also see TimeoutExceptions in some occasions.

Author: AHeise

flink-connector-kafka/src/test/java/org/apache/flink/connector/kafka/sink/KafkaWriterFaultToleranceITCase.java

@@ -67,7 +67,11 @@ void testWriteExceptionWhenKafkaUnavailable() throws Exception {
             try {
                 writer.getCurrentProducer().flush();
                 assertThatCode(() -> writer.write(1, SINK_WRITER_CONTEXT))
-                        .hasRootCauseExactlyInstanceOf(NetworkException.class);
+                        .rootCause()
+                        .matches(
+                                e ->
+                                        e instanceof NetworkException
+                                                || e instanceof TimeoutException);
             } finally {
                 KAFKA_CONTAINER.start();
             }