Run tests with two data layer implementations

[irar2]

What type of PR is this?
/kind cleanup

What this PR does / why we need it:
This PR changes the tests to run with both pkg/epp/backend/metrics and pkg/epp/datalayer.
Which issue(s) this PR fixes:

Fixes #1877

Does this PR introduce a user-facing change?:

NONE

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[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: irar2
Once this PR has been reviewed and has the lgtm label, please assign nirrozenbaum for approval. For more information see the Code Review Process.

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[k8s-ci-robot]

Hi @irar2. Thanks for your PR.

I'm waiting for a github.com member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

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[shmuelk]

/lgtm

[shmuelk]

/ok-to-test

[shmuelk]

/retest

[k8s-ci-robot]

New changes are detected. LGTM label has been removed.

[irar2]

/retest

[shmuelk]

/retest

[k8s-ci-robot]

@irar2: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
pull-gateway-api-inference-extension-verify-main	174ba30	link	true	/test pull-gateway-api-inference-extension-verify-main

Full PR test history. Your PR dashboard. Please help us cut down on flakes by linking to an open issue when you hit one in your PR.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository. I understand the commands that are listed here.