Temporary fix for LeaderElect for kube-scheduler

[dims]

What this PR does / why we need it:

kube-controller-manager defaults --leader-elect to true. We should
do the same for kube-scheduler. kube-scheduler used to have this
set to true, but it got lost during refactoring:

efb2bb7

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes #59729

Special notes for your reviewer:

Release note:

kube-scheduler: restores default leader election behavior. leader-elect command line parameter should "true"

[dims]

/assign @liggitt
/assign @mtaufen

[liggitt]

cc @kubernetes/sig-scheduling-pr-reviews

[liggitt]

/lgtm

needs cherry-pick to 1.9, right?

[dims]

@liggitt yep, here it is #60526

[mtaufen]

/retest

[mtaufen]

/status approve-for-milestone

[bsalamat]

/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: bsalamat, dims, liggitt

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• cmd/kube-scheduler/OWNERS [bsalamat]

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[resouer]

@dims We need to do cherry pick now

[dims]

@resouer the cherry pick is here #60526

[mtaufen]

This isn't merging because it doesn't have status/approved-for-milestone.
Someone with permission to do that needs to add the label.

[liggitt]

this is a bugfix that is required for 1.10 and in process to be backported to 1.9
/status approved-for-milestone

[k8s-github-robot]

[MILESTONENOTIFIER] Milestone Pull Request: Up-to-date for process

@bsalamat @dims @liggitt @mtaufen

Pull Request Labels

• sig/scheduling: Pull Request will be escalated to these SIGs if needed.
• priority/critical-urgent: Never automatically move pull request out of a release milestone; continually escalate to contributor and SIG through all available channels.
• kind/bug: Fixes a bug discovered during the current release.

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[k8s-github-robot]

/test all [submit-queue is verifying that this PR is safe to merge]

[BenTheElder]

/test pull-kubernetes-bazel-build
/test pull-kubernetes-bazel-test

[k8s-github-robot]

/test all [submit-queue is verifying that this PR is safe to merge]

[mtaufen]

/retest

[k8s-github-robot]

/test all [submit-queue is verifying that this PR is safe to merge]

[dims]

/test pull-kubernetes-integration

[BenTheElder]

#60614
/retest

[k8s-github-robot]

/test all [submit-queue is verifying that this PR is safe to merge]

[k8s-github-robot]

Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions here.

[k8s-github-robot]

Commit found in the "release-1.9" branch appears to be this PR. Removing the "cherrypick-candidate" label. If this is an error find help to get your PR picked.

[davidopp]

/approve