Remove gh setup from global proxy test

[mbg]

This is no longer needed by prepare-test.

Risk assessment

For internal use only. Please select the risk level of this change:

• Low risk: Changes are fully under feature flags, or have been fully tested and validated in pre-production environments and are highly observable, or are documentation or test only.

Which use cases does this change impact?

• Testing/None - This change does not impact any CodeQL workflows in production.

How did/will you validate this change?

• End-to-end tests - I am depending on PR checks (i.e. tests in pr-checks).

If something goes wrong after this change is released, what are the mitigation and rollback strategies?

• Rollback - Change can only be disabled by rolling back the release or releasing a new version with a fix.

How will you know if something goes wrong after this change is released?

N/A

Are there any special considerations for merging or releasing this change?

• No special considerations - This change can be merged at any time.

Merge / deployment checklist

• Confirm this change is backwards compatible with existing workflows.
• Consider adding a changelog entry for this change.
• Confirm the readme and docs have been updated if necessary.

[Copilot]

Pull request overview

This PR removes the GitHub CLI setup steps from the global proxy test configuration, as they are no longer needed by the prepare-test action.

Changes:

• Removed container-init-steps section from the global proxy test template that installed GitHub CLI and its dependencies

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
pr-checks/checks/global-proxy.yml	Removed obsolete container-init-steps that installed GitHub CLI in the test container
.github/workflows/__global-proxy.yml	Auto-generated file updated by sync script (per custom guideline 1000000, this file should not be reviewed)