build: Add CPU limits to scanner builds

[msugakov]

Description

See https://www.github.com/konflux-ci/build-definitions/pull/2856. The one is going to re-introduce explicit limits.cpu on all tasks. It may be useful to set our limits.cpu where missing.
Related thread https://redhat-internal.slack.com/archives/C04F4NE15U1/p1759320578511439

I actually don't know what's going to happen when their limits.cpu will be less than our requests.cpu if we don't apply this change.
I tried simulating it locally with #2294 which is most likely what's going to happen once their values are combined with ours and saw this in UI

The task's pod did not even get started and I could not find it in kubectl get pods output.
Here's what came in kubectl events:

61s (x2 over 62s) Warning Failed TaskRun/scanner-on-push-xgxjl-build-container-amd64 failed to create task run pod "scanner-on-push-xgxjl-build-container-amd64": Pod "scanner-on-push-xgxjl-build-container-amd64-pod" is invalid: spec.containers[1].resources.requests: Invalid value: "2": must be less than or equal to cpu limit of 1. Maybe missing or invalid Task rh-acs-tenant/
61s (x2 over 62s) Warning InternalError TaskRun/scanner-on-push-xgxjl-build-container-amd64 1 error occurred:
* failed to create task run pod "scanner-on-push-xgxjl-build-container-amd64": Pod "scanner-on-push-xgxjl-build-container-amd64-pod" is invalid: spec.containers[1].resources.requests: Invalid value: "2": must be less than or equal to cpu limit of 1. Maybe missing or invalid Task rh-acs-tenant/

Validation

Only CI. Checked that amd64 buildah duration did not become longer than other platforms.

[openshift-ci]

Skipping CI for Draft Pull Request.
If you want CI signal for your change, please convert it to an actual PR.
You can still manually trigger a test run with /test all

[openshift-ci]

@msugakov: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
ci/prow/e2e-tests	6dae652	link	false	/test e2e-tests

Full PR test history. Your PR dashboard.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository. I understand the commands that are listed here.