HDFS-17899. Handle InvalidEncryptionKeyException in Balancer Dispatcher, SPS BlockDispatcher and DataNode DataTransfer

[JHSUYU]

JIRA: HDFS-17899

Summary

This is a follow-up of HDFS-17897.

HDFS-17897 fixed InvalidEncryptionKeyException handling in
DFSClient read/write and striped file checksum paths. However, three other
code paths that establish SASL-encrypted connections still lack this handling:

1. Dispatcher.PendingMove.dispatch() — Balancer block moves
2. BlockDispatcher.moveBlock() — SPS block moves
3. DataNode.DataTransfer.run() — DataNode block replication

When dfs.encrypt.data.transfer=true and block keys rotate, these paths fail
with InvalidEncryptionKeyException and the stale key stays cached, causing
all subsequent transfers to fail until process restart.

Fix: Add the same retry pattern to all three paths — catch the exception,
clear the cached encryption key via a new clearDataEncryptionKey() default
method on DataEncryptionKeyFactory, and retry once with a fresh key.

Test

• TestKeyManager#testClearDataEncryptionKey — verifies
  KeyManager.clearDataEncryptionKey() clears cached key
• TestDispatcherEncryptionKey#testClearEncryptionKeyOnRetry — verifies
  Balancer Dispatcher retry
• TestBlockDispatcher#testClearEncryptionKeyOnRetry — verifies SPS
  BlockDispatcher retry
• TestDataTransferEncryptionKey#testClearEncryptionKeyOnRetry — verifies
  DataNode DataTransfer retry

[JHSUYU]

Hi @jojochuang, I have 7 places to fix in total, and I've grouped 3 of them into this PR. Please let me know if these fixes make sense to you.