chore: Add unfinished_work_seconds metric

[jigisha620]

Fixes #N/A

Description Add metric for karpenter_scheduler_unfinished_work_seconds.

How was this change tested? manually tested

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[k8s-ci-robot]

Hi @jigisha620. Thanks for your PR.

I'm waiting for a kubernetes-sigs member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

I understand the commands that are listed here.

Instructions for interacting with me using PR comments are available [here](https://git.k8s.io/community/contributors/guide/pull-requests.md). If you have questions or suggestions related to my behavior, please file an issue against the [kubernetes-sigs/prow](https://github.com/kubernetes-sigs/prow/issues/new?title=Prow%20issue:) repository.

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: jigisha620, jonathan-innis, njtran

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files: - ~~[OWNERS](https://github.com/kubernetes-sigs/karpenter/blob/main/OWNERS)~~ [jonathan-innis,njtran] Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment

[coveralls]

Pull Request Test Coverage Report for Build 11844022526

Details

• 2 of 2 (100.0%) changed or added relevant lines in 1 file are covered.
• 6 unchanged lines in 2 files lost coverage.
• Overall coverage decreased (-0.05%) to 80.77%

---

Files with Coverage Reduction	New Missed Lines	%
pkg/scheduling/requirements.go	2	98.01%
pkg/controllers/disruption/consolidation.go	4	88.55%
<!--	Total:	6		-->

Totals
Change from base Build 11807574057:	-0.05%
Covered Lines:	8472
Relevant Lines:	10489

---

💛 - Coveralls