NO-JIRA: fix(gha) improve robustness by checking for resource existence

[jiridanek]

Depends on

• NO-JIRA: fix(gha): replace oc with kubectl in notebook_controller_integration_test.yaml #417

Description

Without this, the gha is flaky and may fail with

notebook.kubeflow.org/minimal-notebook created
Error from server (NotFound): statefulsets.apps "minimal-notebook" not found

How Has This Been Tested?

GHA

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

[openshift-ci]

Skipping CI for Draft Pull Request.
If you want CI signal for your change, please convert it to an actual PR.
You can still manually trigger a test run with /test all

[jiridanek]

No objections after quite a long time, so it should be good to go. Let's do it the Apache way, commit-then-review. https://www.apache.org/foundation/glossary#CommitThenReview

/lgtm
/approve

[openshift-ci]

@jiridanek: you cannot LGTM your own PR.

In response to this:

No objections after quite a long time, so it should be good to go. Let's do it the Apache way, commit-then-review. https://www.apache.org/foundation/glossary#CommitThenReview

/lgtm
/approve

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[openshift-ci]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: jiridanek

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