bk: update junit-annotate to run faster

[Copilot]

Updated the Buildkite junit-annotate configuration to use faster container-based execution instead of the GCP provider.

Changes Made

• Plugin Version: Upgraded junit-annotate from v2.4.1 to v2.7.0
• Agent Configuration: Replaced provider: "gcp" with image: "docker.elastic.co/ci-agent-images/buildkite-junit-annotate:1.0"
• Execution Mode: Added run-in-docker: false to the plugin configuration
• Preserved Settings: Maintained existing artifacts: "junit-*.xml" and fail-build-on-error: true configurations

The updated configuration follows the pattern specified in the issue, replacing the GCP provider-based setup with a dedicated container image that provides faster execution while maintaining all existing functionality.

Before

- label: ":junit: Junit annotate"
  plugins:
    - junit-annotate#v2.4.1:
        artifacts: "junit-*.xml"
        fail-build-on-error: true
  agents:
    provider: "gcp" #junit plugin requires docker

After

- label: ":junit: Junit annotate"
  agents:
    # requires at least "bash", "curl" and "git"
    image: "docker.elastic.co/ci-agent-images/buildkite-junit-annotate:1.0"
  plugins:
    - junit-annotate#v2.7.0:
        artifacts: "junit-*.xml"
        fail-build-on-error: true
        run-in-docker: false

Fixes #218.

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[v1v]

@copilot finish the PR, it's still marked as WIP in the description

[Copilot]

@copilot finish the PR, it's still marked as WIP in the description

Done! The PR is now complete. I've updated the junit-annotate configuration in .buildkite/pipeline.yml to use the faster container setup as requested in the issue. The changes include:

• Upgraded junit-annotate from v2.4.1 to v2.7.0
• Replaced provider: "gcp" with image: "docker.elastic.co/ci-agent-images/buildkite-junit-annotate:1.0"
• Added run-in-docker: false configuration
• Preserved existing settings for artifacts and fail-build-on-error

The PR is ready for review and no longer WIP. (6e699b1)

[v1v]

buildkite test it

[elasticmachine]

💚 Build Succeeded

• Buildkite Build
• Commit: 6e699b1

cc @v1v @Copilot

[fr4nc1sc0-r4m0n]

LGTM