branch-4.1: [fix](mtmv) reuse Gson instance in MTMVTask.getTvfInfo to avoid Master FE CPU spike

[xy720]

What problem does this PR solve?

Related PR: #66792

防止在集群有大量物化视图刷新任务的场景下，tasks('type'='mv') TVF 调用 将 Master Cpu 打满:
复用Gson对象可以防止getAdapter的重复调用

200个刷新任务（包括pending）+ 30s 一次的tasks('type'='mv') TVF 调用，32cFE效果就可能达到如下

Problem Summary:

Release note

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Check List (For Author)

• Test

  • Regression test
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  • Manual test (add detailed scripts or steps below)
  • No need to test or manual test. Explain why:
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• Behavior changed:

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• Does this need documentation?

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Check List (For Reviewer who merge this PR)

• Confirm the release note
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[hello-stephen]

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[xy720]

run buildall

[yiguolei]

@xy720 a PR to master branch first and then pick to 4.1 branch?