Pipe: Fixed the first-chunk calculation bug for scan parser

[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

[sonarqubecloud]

Quality Gate passed

Issues
2 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 40.05%. Comparing base (f72b3ee) to head (2f9e7c5).
⚠️ Report is 4 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff              @@
##             master   #17597      +/-   ##
============================================
- Coverage     40.05%   40.05%   -0.01%     
  Complexity     2554     2554              
============================================
  Files          5176     5176              
  Lines        348528   348534       +6     
  Branches      44558    44557       -1     
============================================
- Hits         139595   139594       -1     
- Misses       208933   208940       +7     

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