[enhance](insert) support observe insert by show load when loading

[sollhui]

Support observe insert by show load when loading:

*************************** 97. row ***************************
         JobId: 1775813665622
         Label: label_6a5633eadd64c2a_a4a02ef7c3e02cde
         State: PENDING
      Progress: 0%
          Type: INSERT
       EtlInfo: NULL
      TaskInfo: cluster:N/A; timeout(s):14400; max_filter_ratio:0.0
      ErrorMsg: NULL
    CreateTime: 2026-04-10 17:43:34
  EtlStartTime: NULL
 EtlFinishTime: NULL
 LoadStartTime: NULL
LoadFinishTime: NULL
           URL: NULL
    JobDetails: {"ScannedRows":87629968,"LoadBytes":14283684784,"FileNumber":0,"FileSize":0,"TaskNumber":1,"Unfinished backends":[],"All backends":[1775813653513,1775813653511,1775813653509]}
 TransactionId: 0
  ErrorTablets: {}
          User: root
       Comment: 
 FirstErrorMsg:

[hello-stephen]

Thank you for your contribution to Apache Doris.
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Please clearly describe your PR:

1. What problem was fixed (it's best to include specific error reporting information). How it was fixed.
2. Which behaviors were modified. What was the previous behavior, what is it now, why was it modified, and what possible impacts might there be.
3. What features were added. Why was this function added?
4. Which code was refactored and why was this part of the code refactored?
5. Which functions were optimized and what is the difference before and after the optimization?

[sollhui]

run buildall

[hello-stephen]

FE UT Coverage Report

Increment line coverage 100.00% (7/7) 🎉
Increment coverage report
Complete coverage report

[sollhui]

run buildall

[sollhui]

/review

[github-actions]

No issues found in the reviewed patch.

Critical checkpoint conclusions:

• Goal and correctness: The change pre-populates InsertLoadJob auth metadata for running Nereids insert jobs, and the implementation matches that goal.
• Scope/minimality: The patch is small and focused to the affected constructor/call site.
• Concurrency: No new concurrency or lock-order risk was introduced by this change.
• Lifecycle/static init: No special lifecycle or static-initialization concern was introduced.
• Configuration/compatibility: No new config, protocol, or storage-format compatibility impact.
• Parallel paths: The modified Nereids insert path is updated consistently at the shared AbstractInsertExecutor entry point.
• Conditional logic: The new initialization path is straightforward and does not add risky special-case branching.
• Test coverage: No new automated coverage was added in this PR; existing FE tests cover related InsertLoadJob serialization/basic behavior, but the changed running-job auth path remains indirectly covered only.
• Observability: No additional observability appears necessary for this small metadata initialization change.
• Transaction/persistence/data writes: No transaction, persistence-format, or data-correctness issue was identified in the reviewed diff.
• FE/BE variable passing: Not applicable.
• Performance: No meaningful performance concern identified.
• Other issues: None found from the reviewed code paths.

[hello-stephen]

FE UT Coverage Report

Increment line coverage 100.00% (7/7) 🎉
Increment coverage report
Complete coverage report