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

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Details

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