ci(macos): install awscli from brew

[rami3l]

Coming from aws/aws-cli#8858 and https://rust-lang.zulipchat.com/#narrow/stream/242791-t-infra/topic/Strange.20error.20with.20Rustup's.20release.20process.20on.20macOS.20ARM64, it looks like GitHub Actions is installing the x64 version of awscli on macOS ARM64, causing weird segfaults on upload.

This PR tries to install the native awscli from brew instead. It's not guaranteed to work, but AWS might no accept reports running x64 awscli on ARM64 in the first place, so this should be a reasonable move forward.

---

Tested with d696700:

> brew install --overwrite awscli
  which aws
  aws --version
  shell: /bin/bash -e {0}
  env:
    MACOSX_DEPLOYMENT_TARGET: 11
==> Downloading https://ghcr.io/v2/homebrew/core/awscli/manifests/2.17.22
==> Fetching awscli
==> Downloading https://ghcr.io/v2/homebrew/core/awscli/blobs/sha256:5e99263aa00c6f2dfb113b929e40f9c412e7ac7c000fc98d0a231c08b5782c71
==> Pouring awscli--2.17.22.arm64_sonoma.bottle.tar.gz
==> Caveats
The "examples" directory has been installed to:
  /opt/homebrew/share/awscli/examples

Bash completion has been installed to:
  /opt/homebrew/etc/bash_completion.d
==> Summary
🍺  /opt/homebrew/Cellar/awscli/2.17.22: 14,541 files, 127.9MB
/opt/homebrew/bin/aws
aws-cli/2.17.22 Python/3.11.9 Darwin/23.6.0 source/arm64

https://github.com/rust-lang/rustup/actions/runs/10351189934/job/28649168983

> brew install --overwrite awscli
  which aws
  aws --version
  shell: /bin/bash -e {0}
  env:
    MACOSX_DEPLOYMENT_TARGET: 10.12
==> Downloading https://ghcr.io/v2/homebrew/core/awscli/manifests/2.17.27
==> Fetching dependencies for awscli: cffi
==> Downloading https://ghcr.io/v2/homebrew/core/cffi/manifests/1.17.0
==> Fetching cffi
==> Downloading https://ghcr.io/v2/homebrew/core/cffi/blobs/sha256:02f428835ad5ca182e3a336574b63da07ad91f47f634d475376585a31d321c27
==> Fetching awscli
==> Downloading https://ghcr.io/v2/homebrew/core/awscli/blobs/sha256:c6358f1eb00c7ecc080256cdfd4ea67992a4c579eda46473f843a01f2a3e8727
==> Installing dependencies for awscli: cffi
==> Installing awscli dependency: cffi
==> Downloading https://ghcr.io/v2/homebrew/core/cffi/manifests/1.17.0
Already downloaded: /Users/runner/Library/Caches/Homebrew/downloads/7ceab5a46d67fed71a7c5c52fb74da10c3f08bea94026224b4823cd03d783552--cffi-1.17.0.bottle_manifest.json
==> Pouring cffi--1.17.0.ventura.bottle.tar.gz
🍺  /usr/local/Cellar/cffi/1.17.0: 66 files, 1.1MB
==> Installing awscli
==> Pouring awscli--2.17.27.ventura.bottle.tar.gz
==> Caveats
The "examples" directory has been installed to:
  /usr/local/share/awscli/examples

Bash completion has been installed to:
  /usr/local/etc/bash_completion.d
==> Summary
🍺  /usr/local/Cellar/awscli/2.17.27: 14,541 files, 128MB
==> Caveats
==> awscli
The "examples" directory has been installed to:
  /usr/local/share/awscli/examples

Bash completion has been installed to:
  /usr/local/etc/bash_completion.d
/usr/local/bin/aws
aws-cli/2.17.27 Python/3.11.9 Darwin/22.6.0 source/x86_64

https://github.com/rust-lang/rustup/actions/runs/10351189934/job/28649170320

[rami3l]

This patch seems to work.