Fix live search tests that assume an exact result count #1213

The live search test failed in CI run 36746064551 after #1212: test_search_with_n_results requested seven results but the provider returned six. The existing runtime correctly returns available organic results up to n_results; the test incorrectly treats that limit as a guaranteed count.

Agreed workstream: search-result-count-tests.

• Update the equivalent live search assertions to accept positive result counts up to the requested limit, while requiring successful metadata and rejecting provider errors.
• Add deterministic offline cases for zero, fewer, exactly, and more results than requested to verify the existing cap.
• Keep runtime, Gemini configuration, caching, and deployment behavior unchanged.