Address PR review comments

Author: KonstantinMi

lib/src/main/java/com/google/cloud/datalineage/producerclient/v1/AsyncLineageProducerClient.java

@@ -196,7 +196,7 @@ private void gracefulShutdown(Instant shutdownStartedAt) throws InterruptedExcep
     if (gracefulShutdownDuration.isZero()) {
       log.warn(
           "AsyncLineageProducerClient graceful shutdown duration was set to zero. "
-              + "This effectively means hard shutdown");
+              + "This effectively means hard shutdown with potential data loss");
       return;
     }
     log.debug("Starting graceful shutdown with duration: {}", gracefulShutdownDuration);

lib/src/test/java/com/google/cloud/datalineage/producerclient/v1/AsyncLineageProducerClientLoggingTest.java

@@ -183,7 +183,7 @@ public void testHardShutdownLogging() throws Exception {
     assertThat(testAppender.getMessagesAtLevel(Level.WARN))
         .contains(
             "AsyncLineageProducerClient graceful shutdown duration was set to zero. "
-                + "This effectively means hard shutdown");
+                + "This effectively means hard shutdown with potential data loss");
   }
 
   @Test