GH-50573: [CI][C++] Remove brew workaround for aws-sdk-cpp

[pitrou]

Rationale for this change

In #50254 we introduced an explicit brew install aws-sdk-cpp step in order to workaround a bug in brew. However, the latter bug has since been fixed and we can now remove the workaround.

Are these changes tested?

By existing CI jobs.

Are there any user-facing changes?

No.

• GitHub Issue: [CI][C++] Remove brew workaround for aws-sdk-cpp #50573

[github-actions]

Thanks for opening a pull request!

If this is not a minor PR. Could you open an issue for this pull request on GitHub? https://github.com/apache/arrow/issues/new/choose

Opening GitHub issues ahead of time contributes to the Openness of the Apache Arrow project.

Then could you also rename the pull request title in the following format?

GH-${GITHUB_ISSUE_ID}: [${COMPONENT}] ${SUMMARY}

or

MINOR: [${COMPONENT}] ${SUMMARY}

See also:

• Other pull requests
• Contribution Guidelines - Contributing Overview

[github-actions]

⚠️ GitHub issue #50573 has been automatically assigned in GitHub to PR creator.

[pitrou]

@github-actions crossbow submit preview-docs verify-rc-source--macos-

[github-actions]

Revision: 3de4b47

Submitted crossbow builds: ursacomputing/crossbow @ actions-c984dc80ea

Task	Status
preview-docs
verify-rc-source-cpp-macos-amd64
verify-rc-source-integration-macos-amd64
verify-rc-source-python-macos-amd64
verify-rc-source-ruby-macos-amd64

[github-actions]

Revision: 3de4b47

Submitted crossbow builds: ursacomputing/crossbow @ actions-6e31d87696

Task	Status
preview-docs
verify-rc-source-cpp-macos-amd64
verify-rc-source-cpp-macos-arm64
verify-rc-source-cpp-macos-conda-amd64
verify-rc-source-integration-macos-amd64
verify-rc-source-integration-macos-arm64
verify-rc-source-integration-macos-conda-amd64
verify-rc-source-python-macos-amd64
verify-rc-source-python-macos-arm64
verify-rc-source-python-macos-conda-amd64
verify-rc-source-ruby-macos-amd64
verify-rc-source-ruby-macos-arm64

[conbench-apache-arrow]

After merging your PR, Conbench analyzed the 4 benchmarking runs that have been run so far on merge-commit 8943fcc.

There was 1 benchmark result indicating a performance regression:

• Commit Run on test-mac-arm at 2026-07-22 12:31:58Z
  • tpch (R) with engine=arrow, format=parquet, language=R, memory_map=False, query_id=TPCH-22, scale_factor=1

The full Conbench report has more details. It also includes information about 78 possible false positives for unstable benchmarks that are known to sometimes produce them.