bazel: Update c-ares to v1.34.6

[michael-redpanda]

Update c-ares to address CVE-2025-62408

Backports Required

• none - not a bug fix
• none - this is a backport
• none - issue does not exist in previous branches
• none - papercut/not impactful enough to backport
• v25.3.x
• v25.2.x
• v25.1.x

Release Notes

Bug Fixes

• Updated C-Ares to 1.34.6 to address CVE-2025-62408

[vbotbuildovich]

/backport v25.3.x

[vbotbuildovich]

/backport v25.2.x

[vbotbuildovich]

Failed to create a backport PR to v25.3.x branch. I tried:

git remote add upstream https://github.com/redpanda-data/redpanda.git
git fetch --all
git checkout -b backport-pr-29036-v25.3.x-814 remotes/upstream/v25.3.x
git cherry-pick -x 99dd3ea4f8

Workflow run logs.

[vbotbuildovich]

Failed to create a backport PR to v25.2.x branch. I tried:

git remote add upstream https://github.com/redpanda-data/redpanda.git
git fetch --all
git checkout -b backport-pr-29036-v25.2.x-323 remotes/upstream/v25.2.x
git cherry-pick -x 99dd3ea4f8

Workflow run logs.