[branch-4.1][fix](load) Avoid global BE auth precheck for stream load (#66629)

[gavinchou]

Pick #66629 to branch-4.1.

Original PR: #66629
Cherry-picked from: bd12e5a
Backport note: branch-4.1 does not have HttpRequest::mark_send_reply(), so the master-only call was dropped while resolving stream_load.cpp.

Validation:

• sh format_code.sh on the changed BE C++ files
• ninja -C be/ut_build_ASAN -j 39 doris_be_test
• doris_be_test --gtest_filter=StreamLoadTest.*:HttpAuthTest.* (9 tests passed)

[gavinchou]

run buildall

[gavinchou]

/review

[hello-stephen]

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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?

[github-actions]

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[yiguolei]

skip buildall

[github-actions]

PR approved by at least one committer and no changes requested.

[github-actions]

PR approved by anyone and no changes requested.