Restore null pointer from checkpoint

### Search before asking

- [x] I had searched in the [issues](https://github.com/apache/seatunnel/issues?q=is%3Aissue+label%3A%22bug%22) and found no similar issues.

### What happened

从检查点恢复报空指针

### SeaTunnel Version

2.3.11

### SeaTunnel Config

```conf
vim config/seatunnel.yaml

seatunnel:
engine:
classloader-cache-mode: true
history-job-expire-minutes: 1440
backup-count: 1
queue-type: blockingqueue
print-execution-info-interval: 60
print-job-metrics-info-interval: 60
job-schedule-strategy: WAIT
slot-service:
dynamic-slot: false
slot-num: 20
coordinator-service:
core-thread-num: 30
max-thread-num: 1000
checkpoint:
interval: 30000
timeout: 60000
storage:
type: hdfs
max-retained: 5
plugin-config:
storage.type: hdfs
fs.defaultFS: file:///
http:
enable-http: true
port: 8080
enable-dynamic-port: false
enable-basic-auth: true
```

### Running Command

```shell
./bin/seatunnel.sh -r 1008623309102776321 -c /opt/module/seatunnel/conf/hdfs_2_mongo5.conf
```

### Error Exception

```log
[1008623309102776321] 2025-08-15 14:29:52,872 ERROR [.s.e.s.c.CheckpointCoordinator] [hz.main.generic-operation.thread-24] - report error from task
org.apache.seatunnel.common.utils.SeaTunnelException: java.lang.RuntimeException: java.util.concurrent.ExecutionException: java.lang.NullPointerException
at org.apache.seatunnel.engine.server.task.flow.SourceFlowLifeCycle.restoreState(SourceFlowLifeCycle.java:378)
at org.apache.seatunnel.engine.server.task.SeaTunnelTask.lambda$restoreState$16(SeaTunnelTask.java:401)
at java.util.stream.ForEachOps$ForEachOp$OfRef.accept(ForEachOps.java:184)
at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193)
at java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:175)
at java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1382)
at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:481)
at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:471)
at java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:151)
at java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:174)
at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
at java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:418)
at org.apache.seatunnel.engine.server.task.SeaTunnelTask.restoreState(SeaTunnelTask.java:398)
at org.apache.seatunnel.engine.server.checkpoint.operation.NotifyTaskRestoreOperation.lambda$null$0(NotifyTaskRestoreOperation.java:107)
at java.util.concurrent.CompletableFuture$AsyncRun.run(CompletableFuture.java:1626)
at org.apache.seatunnel.api.tracing.MDCRunnable.run(MDCRunnable.java:43)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)
Caused by: java.util.concurrent.ExecutionException: java.lang.NullPointerException
at com.hazelcast.spi.impl.operationservice.impl.InvocationFuture.returnOrThrowWithGetConventions(InvocationFuture.java:121)
at com.hazelcast.spi.impl.operationservice.impl.InvocationFuture.resolveAndThrowIfException(InvocationFuture.java:100)
at com.hazelcast.spi.impl.AbstractInvocationFuture.get(AbstractInvocationFuture.java:617)
at org.apache.seatunnel.engine.server.task.flow.SourceFlowLifeCycle.restoreState(SourceFlowLifeCycle.java:375)
... 18 more
Caused by: java.lang.NullPointerException
at ------ submitted from ------.()
at com.hazelcast.internal.util.ExceptionUtil.cloneExceptionWithFixedAsyncStackTrace(ExceptionUtil.java:336)
at com.hazelcast.spi.impl.operationservice.impl.InvocationFuture.returnOrThrowWithGetConventions(InvocationFuture.java:112)
... 21 more

at org.apache.seatunnel.engine.server.checkpoint.CheckpointCoordinator.reportCheckpointErrorFromTask(CheckpointCoordinator.java:397) ~[seatunnel-starter.jar:2.3.11]
at org.apache.seatunnel.engine.server.checkpoint.CheckpointManager.reportCheckpointErrorFromTask(CheckpointManager.java:182) ~[seatunnel-starter.jar:2.3.11]
at org.apache.seatunnel.engine.server.checkpoint.operation.CheckpointErrorReportOperation.runInternal(CheckpointErrorReportOperation.java:48) ~[seatunnel-starter.jar:2.3.11]
at org.apache.seatunnel.engine.server.task.operation.TracingOperation.run(TracingOperation.java:42) ~[seatunnel-starter.jar:2.3.11]
at com.hazelcast.spi.impl.operationservice.Operation.call(Operation.java:189) ~[seatunnel-starter.jar:2.3.11]
at com.hazelcast.spi.impl.operationservice.impl.OperationRunnerImpl.call(OperationRunnerImpl.java:273) ~[seatunnel-starter.jar:2.3.11]
at com.hazelcast.spi.impl.operationservice.impl.OperationRunnerImpl.run(OperationRunnerImpl.java:248) ~[seatunnel-starter.jar:2.3.11]
at com.hazelcast.spi.impl.operationservice.impl.OperationRunnerImpl.run(OperationRunnerImpl.java:471) ~[seatunnel-starter.jar:2.3.11]
at com.hazelcast.spi.impl.operationexecutor.impl.OperationThread.process(OperationThread.java:197) ~[seatunnel-starter.jar:2.3.11]
at com.hazelcast.spi.impl.operationexecutor.impl.OperationThread.process(OperationThread.java:137) ~[seatunnel-starter.jar:2.3.11]
at com.hazelcast.spi.impl.operationexecutor.impl.OperationThread.executeRun(OperationThread.java:123) ~[seatunnel-starter.jar:2.3.11]
at com.hazelcast.internal.util.executor.HazelcastManagedThread.run(HazelcastManagedThread.java:102) ~[seatunnel-starter.jar:2.3.11]
[1008623309102776321] 2025-08-15 14:29:52,873 INFO [.s.e.s.c.CheckpointCoordinator] [hz.main.generic-operation.thread-24] - Turn checkpoint_state_1008623309102776321_1 state from RUNNING to FAILED
```

### Zeta or Flink or Spark Version

2.3.11

### Java or Scala Version

1.8

### Screenshots

可以执行savepoint但是不能恢复

### Are you willing to submit PR?

- [ ] Yes I am willing to submit a PR!

### Code of Conduct

- [x] I agree to follow this project's [Code of Conduct](https://www.apache.org/foundation/policies/conduct)

Start by reproducing the checkpoint restore with the provided SeaTunnel 2.3.11 command and configuration, then inspect SourceFlowLifeCycle.restoreState at lines 375-378 and SeaTunnelTask.restoreState at lines 398-401. Trace the reported null pointer through the checkpoint restore path; done means the saved checkpoint restores successfully without the NullPointerException.

Written by the indexing model from the issue text.