[Fix](p0) rename duplicate pyudf across p0 suites

[linrrzqqq]

Problem Summary:

prevent failures caused by conflicting function names across test suites.

Exception in pythonudf_p0/test_pythonudf_mixed_params.groovy(line 242):
sql """ DROP FUNCTION IF EXISTS py_vec_add_int(INT, INT); """
// If another suite creates a function with the same name at this time, it will cause the test to fail.
sql """
CREATE FUNCTION py_vec_add_int(INT, INT)
Exception:
java.sql.SQLException: errCode = 2, detailMessage = function already exists

[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?

[linrrzqqq]

run buildall

[linrrzqqq]

/review

[github-actions]

Code review completed. I did not find blocking issues in this PR.\n\nCritical checkpoint conclusions:\n- Goal and test proof: The PR aims to avoid duplicate Python UDF names across p0 regression suites. The changed function declarations, invocations, inline symbols where needed, and cleanup statements are consistent; existing qt checks continue to cover the renamed UDF calls.\n- Scope: The change is small and focused on test-only UDF renames.\n- Concurrency/lifecycle/config/compatibility/persistence/data writes: Not applicable; this is regression test SQL/Groovy cleanup and UDF naming only.\n- Parallel code paths: I checked the affected old and new names in pythonudf_p0 and pythonudf_complex_p0; the renamed names are unique, while remaining same-name functions are distinct existing tests outside the edited instances.\n- Test coverage/results: No .out updates are required because the query result labels and outputs are unchanged. I did not run the regression suites in this runner.\n- Observability/performance: Not applicable for this test-only rename.\n\nUser focus: No additional user-provided review focus was specified.