TableBucketStateMachine should consider NonExistentBucket as a valid previous state

`com.alibaba.fluss.server.coordinator.TableManagerITCase#testPartitionedTableManagement` has many ERROR logs that reporting

```
5017 [coordinator-event-thread] ERROR com.alibaba.fluss.server.coordinator.statemachine.TableBucketStateMachine [] - Table bucket TableBucket{tableId=0, partitionId=0, bucket=0, tablePath=db1.tb1_YEAR, partition=2025} should be one of [OnlineBucket, NewBucket, OfflineBucket] states before moving to OfflineBucket state. Instead it is in NonExistentBucket.
5018 [coordinator-event-thread] ERROR com.alibaba.fluss.server.coordinator.statemachine.TableBucketStateMachine [] - Fail to change state for table bucket TableBucket{tableId=0, partitionId=0, bucket=0, tablePath=db1.tb1_YEAR, partition=2025} from NonExistentBucket to OfflineBucket.
5018 [coordinator-event-thread] ERROR com.alibaba.fluss.server.coordinator.statemachine.TableBucketStateMachine [] - Table bucket TableBucket{tableId=0, partitionId=0, bucket=0, tablePath=db1.tb1_YEAR, partition=2025} should be one of [OnlineBucket, NewBucket, OfflineBucket] states before moving to OnlineBucket state. Instead it is in NonExistentBucket.
5018 [coordinator-event-thread] ERROR com.alibaba.fluss.server.coordinator.statemachine.TableBucketStateMachine [] - Fail to change state for table bucket TableBucket{tableId=0, partitionId=0, bucket=0, tablePath=db1.tb1_YEAR, partition=2025} from NonExistentBucket to OnlineBucket.
```

This is similar to https://github.com/alibaba/fluss/issues/764

Start with com.alibaba.fluss.server.coordinator.statemachine.TableBucketStateMachine and the TableManagerITCase#testPartitionedTableManagement test. Reproduce the reported ERROR logs and trace the transition from NonExistentBucket to OfflineBucket or OnlineBucket. Done means the test no longer reports these invalid-state transition errors.

Written by the indexing model from the issue text.