Re-add missing metric: pod_preemption.attempts

[arapulido]

What does this PR do?

It changes the metric called scheduler_total_preemption_attempts to scheduler_preemption_attempts_total, from 1.19.

Motivation

This metric changed its name in 1.19 and the integration was never changed, so the metric pod_preemption.attempts was missing in newer versions of Kubernetes

Details in the K8s changelog: https://www-1.muraena.okta-security-dev.com/kubernetes/kubernetes/blob/master/CHANGELOG/CHANGELOG-1.19.md#other-cleanup-or-flake-7

Review checklist (to be filled by reviewers)

• Feature or bugfix MUST have appropriate tests (unit, integration, e2e)
• PR title must be written as a CHANGELOG entry (see why)
• Files changes must correspond to the primary purpose of the PR as described in the title (small unrelated changes should have their own PR)
• PR must have changelog/ and integration/ labels attached

[codecov]

Codecov Report

Merging #12656 (f6cc73a) into master (39aa394) will increase coverage by 0.00%.
The diff coverage is 100.00%.

Flag	Coverage Δ
kube_scheduler	97.02% <100.00%> (+0.02%)	⬆️

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