Run validation tasks against nightly deployments

[mjnagel]

Related to #213

Currently our nightly testing simply deploys core on top of a given infrastructure and then removes + destroys it (see EKS example). To ensure proper coverage of testing here we should at minimum run our existing validation tasks. Note that this may require some additional work to ensure endpoints are reachable by the github runner (potentially via /etc/hosts modifications + public load balancers?).

Any expansion to validations/testing is out of scope for this ticket. While some validations may need updates to function in the nightly testing, this ticket is focused on running the existing validations rather than expanding testing (that will be covered in other work).

Definition of done: Validation tasks are run as part of nightly testing (and passing).

[mjnagel]

Added context: Current tests run with a combination of uds tasks (basic validations) and jest/playwright (e2e). We would want to account for DNS/properly resolving for both of these.

Helpful ref links for ref-arch testing:

• https://github.com/defenseunicorns/uds-aws-eks-reference-deployment/blob/ec595344f42ca6c3273da3f7532f9bda513a8a28/test/e2e/e2e_test.go#L30
• https://github.com/defenseunicorns/uds-reference-deployments/blob/main/aws/eks/core/tasks/test.yaml