Pipe: Fixed the NPE of tree privilege check

[Caideyipi]

Description

As the title said.

---

This PR has:

• been self-reviewed.
  • concurrent read
  • concurrent write
  • concurrent read and write
• added documentation for new or modified features or behaviors.
• added Javadocs for most classes and all non-trivial methods.
• added or updated version, license, or notice information
• added comments explaining the "why" and the intent of the code wherever would not be obvious
  for an unfamiliar reader.
• added unit tests or modified existing tests to cover new code paths, ensuring the threshold
  for code coverage.
• added integration tests.
• been tested in a test IoTDB cluster.

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Key changed/added classes (or packages if there are too many classes) in this PR

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 39.33%. Comparing base (c563f96) to head (60a7914).

Additional details and impacted files

@@             Coverage Diff              @@
##             master   #17006      +/-   ##
============================================
+ Coverage     39.22%   39.33%   +0.11%     
  Complexity      212      212              
============================================
  Files          5080     5080              
  Lines        340604   340606       +2     
  Branches      43482    43482              
============================================
+ Hits         133585   133983     +398     
+ Misses       207019   206623     -396     

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[sonarqubecloud]

Quality Gate failed

Failed conditions
C Maintainability Rating on New Code (required ≥ A)

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