Change smoke test to trigger from a pr opened against stable

[abaiken]

Feature description:

Currently our smoke tests are triggered when you tag a PR as stable. We should change the smoke test to run when a PR is opened agains the e2e repo.

Is your feature request related to a problem?

We need to be able to tag an image as stable in order to deploy to production.

Describe the solution you'd like

Change smoke test to run when a PR is opened against the stable branch.

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Acceptance Criteria:

• [ ] Verify that smoke tests are triggered when a PR is opened to smoke test repo.

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