[test] Unstable test FlinkUnionReadPrimaryKeyTableITCase.testUnionReadInStreamMode

[github-actions]

https://github.com/apache/fluss/actions/runs/23418545308/job/68118735366

[ERROR] org.apache.fluss.lake.iceberg.flink.FlinkUnionReadPrimaryKeyTableITCase.testUnionReadInStreamMode(Boolean)[1]  Time elapsed: 121.495 s  <<< FAILURE!
java.lang.AssertionError: bucket TableBucket{tableId=2, bucket=0} not synced
	at org.apache.fluss.testutils.common.CommonTestUtils.waitUntil(CommonTestUtils.java:81)
	at org.apache.fluss.testutils.common.CommonTestUtils.waitUntil(CommonTestUtils.java:99)
	at org.apache.fluss.lake.iceberg.testutils.FlinkIcebergTieringTestBase.waitUntilBucketSynced(FlinkIcebergTieringTestBase.java:525)
	at org.apache.fluss.lake.iceberg.testutils.FlinkIcebergTieringTestBase.waitUntilBucketSynced(FlinkIcebergTieringTestBase.java:519)
	at org.apache.fluss.lake.iceberg.flink.FlinkUnionReadPrimaryKeyTableITCase.testUnionReadInStreamMode(FlinkUnionReadPrimaryKeyTableITCase.java:78)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
	at org.junit.platform.commons.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:727)
	at org.junit.jupiter.engine.execution.MethodInvocation.proceed(MethodInvocation.java:60)
	at org.junit.jupiter.engine.execution.InvocationInterceptorChain$ValidatingInvocation.proceed(InvocationInterceptorChain.java:131)
	at org.junit.jupiter.engine.extension.TimeoutExtension.intercept(TimeoutExtension.java:156)
	at org.junit.jupiter.engine.extension.TimeoutExtension.interceptTestableMethod(TimeoutExtension.java:147)
	at org.junit.jupiter.engine.extension.TimeoutExtension.interceptTestTemplateMethod(TimeoutExtension.java:94)
	at org.junit.jupiter.engine.execution.InterceptingExecutableInvoker$ReflectiveInterceptorCall.lambda$ofVoidMethod$0(InterceptingExecutableInvoker.java:103)
	at org.junit.jupiter.engine.execution.InterceptingExecutableInvoker.lambda$invoke$0(InterceptingExecutableInvoker.java:93)
	at org.junit.jupiter.engine.execution.InvocationInterceptorChain$InterceptedInvocation.proceed(InvocationInterceptorChain.java:106)
	at org.junit.jupiter.engine.execution.InvocationInterceptorChain.proceed(InvocationInterceptorChain.java:64)
	at org.junit.jupiter.engine.execution.InvocationInterceptorChain.chainAndInvoke(InvocationInterceptorChain.java:45)
	at org.junit.jupiter.engine.execution.InvocationInterceptorChain.invoke(InvocationInterceptorChain.java:37)
	at org.junit.jupiter.engine.execution.InterceptingExecutableInvoker.invoke(InterceptingExecutableInvoker.java:92)
	at org.junit.jupiter.engine.execution.InterceptingExecutableInvoker.invoke(InterceptingExecutableInvoker.java:86)
	at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.lambda$invokeTestMethod$7(TestMethodTestDescriptor.java:217)
	at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
	at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.invokeTestMethod(TestMethodTestDescriptor.java:213)
	at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:138)
	at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:68)
... (truncated)