[chore] ok-to-test label should run CI workflows on non Kubeflow members' PRs

[DharmitD]

As of now, if a non-Kubeflow member proposes a PR to the KFP repo, the CI workflow runs don't get triggered automatically on applying the ok-to-test label. Only repo maintainers have the permission to trigger the CI runs in this case:

KSC would like to grow the community size so PR coming from non-members will probably be more frequent.
As this approach isn't scalable, we need to update ok-to-test functionality to have CI workflows run automatically on PRs from non-members as well.

[hbelmiro]

Duplicates #10981.
/close

[google-oss-prow]

@hbelmiro: Closing this issue.

In response to this:

Duplicates #10981.
/close

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