Revert "Backend - Starting the api-server container build from scratch"

[Ark-kun]

Reverts #1699

There are some unusual failures in #1739, so let's rollback the CL for now.

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This change is 

[IronPan]

/lgtm
/approve
/retest

[k8s-ci-robot]

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This pull-request has been approved by: IronPan

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[IronPan]

/retest

[IronPan]

/retest

[IronPan]

/retest

[IronPan]

I'll force submit this so we could test on the actual api server.
Let's use #1736 to track if tests passed.

[k8s-ci-robot]

@Ark-kun: The following tests failed, say /retest to rerun them all:

Test name	Commit	Details	Rerun command
kubeflow-pipeline-sample-test	b0b759b	link	/test kubeflow-pipeline-sample-test
kubeflow-pipeline-e2e-test	b0b759b	link	/test kubeflow-pipeline-e2e-test

Full PR test history. Your PR dashboard. Please help us cut down on flakes by linking to an open issue when you hit one in your PR.

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