Add `karpenter_pods_drained_total` during Node drain

[jonathan-innis]

Description

What problem are you trying to solve?

It's useful to know how many pods are drained by a particular reason in the same way it's useful to know how many Nodes are drained by a particular reason (which we should also consider adding to the Prom metric). We basically need to add a Inc() on this counter metric each time we successfully drain a pod here.

How important is this feature to you?

Would provide more visibility into the number of pods that end up being drained by a particular reason

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[jonathan-innis]

/triage accepted
/priority important-soon
/help
/good-first-issue

[k8s-ci-robot]

@jonathan-innis:
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In response to this:

/triage accepted
/priority important-soon
/help
/good-first-issue

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[omerap12]

I would love to help :)
/assign