[release-4.21] OCPBUGS-88473: Add an agent flag to disable installing boatloaders

[sunku5494]

Pipes the new agent flag (enable_bios_bootloader_install) to agents. This flag disables bootloader install (calls to grub-install) by default for security reasons.

Part of mitigation of CVE-2026-43003.

Related-Bug: 2148310
Change-Id: I694bbe121e09e7e0b2e6c5ab3746f7943385190a

(cherry picked from commit e38ae0c) (cherry picked from commit 9a8d91a)

[openshift-ci-robot]

@sunku5494: This pull request references Jira Issue OCPBUGS-88473, which is invalid:

• release note text must be set and not match the template OR release note type must be set to "Release Note Not Required". For more information you can reference the OpenShift Bug Process.
• expected Jira Issue OCPBUGS-88473 to depend on a bug targeting a version in 4.22.0 and in one of the following states: VERIFIED, RELEASE PENDING, CLOSED (ERRATA), CLOSED (CURRENT RELEASE), CLOSED (DONE), CLOSED (DONE-ERRATA), but no dependents were found

Comment /jira refresh to re-evaluate validity if changes to the Jira bug are made, or edit the title of this pull request to link to a different bug.

The bug has been updated to refer to the pull request using the external bug tracker.

Details

In response to this:

Pipes the new agent flag (enable_bios_bootloader_install) to agents. This flag disables bootloader install (calls to grub-install) by default for security reasons.

Part of mitigation of CVE-2026-43003.

Related-Bug: 2148310
Change-Id: I694bbe121e09e7e0b2e6c5ab3746f7943385190a

(cherry picked from commit e38ae0c) (cherry picked from commit 9a8d91a)

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[openshift-ci]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: sunku5494
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[openshift-ci]

@sunku5494: all tests passed!

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