[FLINK-24082][python] Fix Python UDTF to handle properly when the result is a generator of Row

[dianfu]

What is the purpose of the change

(For example: This pull request makes task deployment go through the blob server, rather than through RPC. That way we avoid re-transferring them on each deployment (during recovery).)

Brief change log

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• The TaskInfo is stored in the blob store on job creation time as a persistent artifact
• Deployments RPC transmits only the blob storage reference
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Verifying this change

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This change is a trivial rework / code cleanup without any test coverage.

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• Added integration tests for end-to-end deployment with large payloads (100MB)
• Extended integration test for recovery after master (JobManager) failure
• Added test that validates that TaskInfo is transferred only once across recoveries
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Documentation

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[HuangXingBo]

change to from collections import Iterable, Generator?

[HuangXingBo]

put these two imports together with other python imports

[HuangXingBo]

change to from collections import Iterable, Generator and put this import after the import struct