[test] Unstable test Flink118TableSourceBatchITCase.testLogTableBatchScanSupportsNonFullStartupMode

https://github.com/apache/fluss/actions/runs/30948293084/job/92123675584

```
[ERROR] org.apache.fluss.flink.source.Flink118TableSourceBatchITCase.testLogTableBatchScanSupportsNonFullStartupMode Time elapsed: 3.764 s <<< ERROR!
java.lang.RuntimeException: Unexpected error after waiting 2633 ms for Flink job results. Expected 1 records but got 0 before error occurred.
at org.apache.fluss.flink.source.testutils.FlinkRowAssertionsUtils.collectRowsWithTimeout(FlinkRowAssertionsUtils.java:169)
at org.apache.fluss.flink.source.testutils.FlinkRowAssertionsUtils.collectRowsWithTimeout(FlinkRowAssertionsUtils.java:105)
at org.apache.fluss.flink.source.testutils.FlinkRowAssertionsUtils.collectRowsWithTimeout(FlinkRowAssertionsUtils.java:93)
at org.apache.fluss.flink.source.FlinkTableSourceBatchITCase.testLogTableBatchScanSupportsNonFullStartupMode(FlinkTableSourceBatchITCase.java:516)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
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$ValidatingInvocation.proceed(InvocationInterceptorChain.java:131)
at org.junit.jupiter.engine.extension.TimeoutExtension.intercept(TimeoutExtension.java:156)
at org.junit.jupiter.engine.extension.TimeoutExtension.interceptTestableMethod(TimeoutExtension.java:147)
at org.junit.jupiter.engine.extension.TimeoutExtension.interceptTestMethod(TimeoutExtension.java:86)
at org.junit.jupiter.engine.execution.InterceptingExecutableInvoker$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$7(TestMethodTestDescriptor.java:217)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.invokeTestMethod(TestMethodTestDescriptor.java:213)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:138)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:68)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$6(NodeTestTask.java:151)
... (truncated)
```

Start with FlinkTableSourceBatchITCase.testLogTableBatchScanSupportsNonFullStartupMode and the failure path in FlinkRowAssertionsUtils.collectRowsWithTimeout. Reproduce the linked CI failure and determine why the test receives zero records before the timeout. Done means the test reliably collects the expected one record without the reported error.

Written by the indexing model from the issue text.