Fix ML Pipelines Tests

[rimolive]

Fix the ML Pipelines CI Tests #653

Description

A change in how to check if the Pipeline Run exists after creation was added

How Has This Been Tested?

$ cd tests
$ make tests
$ make run TESTS_REGEX=ml-pipelines

Merge criteria:

• The commits are squashed in a cohesive manner and have meaningful messages.
• Testing instructions have been added in the PR body (for PRs involving changes that are not immediately obvious).
• The developer has manually tested the changes and verified that the changes work

[LaVLaS]

@rimolive I ran another test on OCP 4.11 and it appears like the kfp pipeline api server is not deleting the PipelineRun object during the delete_pipeline function. Can you confirm that it is passing on an OCP 4.10 cluster and the PipelineRun object is deleted after curl -s -X DELETE ${ROUTE}/apis/v1beta1/pipelines/${PIPELINE_ID} runs successfully?

[LaVLaS]

/lgtm

Manual execution on an OCP 4.11 cluster worked without any issues

[openshift-ci]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: LaVLaS

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[DharmitD]

/lgtm