[CI/Build] Skip prompt embeddings tests on V1-only CPU backend

[bigPYJ1151]

Purpose

• For now prompt embeddings fallbacks to V0, which has been deprecated on CPU backend. Skip related tests temporarily, which can be recovered after [CORE] Prompt Embeddings Support for v1 Engine #24278 merged

Test Plan

CI tests

Test Result

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Essential Elements of an Effective PR Description Checklist

• The purpose of the PR, such as "Fix some issue (link existing issues this PR will resolve)".
• The test plan, such as providing test command.
• The test results, such as pasting the results comparison before and after, or e2e results
• (Optional) The necessary documentation update, such as updating supported_models.md and examples for a new model.
• (Optional) Release notes update. If your change is user facing, please update the release notes draft in the Google Doc.

[gemini-code-assist]

Code Review

This pull request introduces a temporary measure to skip tests for prompt embeddings on the V1-only CPU backend. The rationale is that prompt embeddings currently fall back to the V0 backend, which is deprecated on CPU. The change correctly uses pytest.skip to bypass these specific test configurations, and a helpful comment points to the future pull request that will resolve the underlying issue. The implementation is sound and serves as a good interim solution to maintain CI stability.

[qthequartermasterman]

Thank you for catching this!