[fix](build) Fix insecure Python dependency pins in doris-compose, dbt-doris, and cost_model

[arpitjain099]

What problem does this PR solve?

Issue Number: N/A

Related PR: #63188

Problem Summary:
Three Python requirements files have dependency pins that allow installing versions with known security issues.

docker/runtime/doris-compose/requirements.txt

The requests<=2.31.0 constraint sets an upper bound but no lower bound, so pip can resolve to any version below 2.31.0. Versions before 2.31.0 are affected by CVE-2023-32681 (Proxy-Authorization header leaked on cross-domain redirects). Changed to requests>=2.31.0 to set a secure floor.

extension/dbt-doris/dev-requirements.txt

The mysql-connector-python>=8.0.0,<8.3 lower bound allows versions with known authentication bypass issues. Raised the lower bound to >=8.0.33 which includes the relevant fixes.

tools/cost_model_evaluate/requirements.txt

The mysql_connector_repackaged==0.3.1 package is an unofficial third-party repackage of the MySQL connector whose last PyPI release was in 2014. Replaced with the official mysql-connector-python>=8.0.33,<9 package. The code in sql_executor.py imports mysql.connector which both packages provide, so this is a drop-in replacement.

Release note

None

Check List (For Author)

• Test

  • Regression test
  • Unit Test
  • Manual test (add detailed scripts or steps below)
    • Verified that pip install -r docker/runtime/doris-compose/requirements.txt resolves correctly with the new pin.
    • Confirmed sql_executor.py imports mysql.connector (the standard interface), not the repackaged module name.
  • No need to test or manual test. Explain why:
    • This is a refactor/code format and no logic has been changed.
    • Previous test can cover this change.
    • No code files have been changed.
    • Other reason

• Behavior changed:

  • No.

• Does this need documentation?

  • No.

[hello-stephen]

Thank you for your contribution to Apache Doris.
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