rename response to responses in verifications, update provider

tests/verifications/openai_api/fixtures/test_cases/response.yaml

@@ -1,65 +0,0 @@
-test_response_basic:
-  test_name: test_response_basic
-  test_params:
-    case:
-    - case_id: "earth"
-      input: "Which planet do humans live on?"
-      output: "earth"
-    - case_id: "saturn"
-      input: "Which planet has rings around it with a name starting with letter S?"
-      output: "saturn"
-
-test_response_multi_turn:
-  test_name: test_response_multi_turn
-  test_params:
-    case:
-    - case_id: "earth"
-      turns:
-      - input: "Which planet do humans live on?"
-        output: "earth"
-      - input: "What is the name of the planet from your previous response?"
-        output: "earth"
-
-test_response_web_search:
-  test_name: test_response_web_search
-  test_params:
-    case:
-    - case_id: "llama_experts"
-      input: "How many experts does the Llama 4 Maverick model have?"
-      tools:
-      - type: web_search
-        search_context_size: "low"
-      output: "128"
-
-test_response_image:
-  test_name: test_response_image
-  test_params:
-    case:
-    - case_id: "llama_image"
-      input:
-      - role: user
-        content:
-        - type: input_text
-          text: "Identify the type of animal in this image."
-        - type: input_image
-          image_url: "https://upload.wikimedia.org/wikipedia/commons/f/f7/Llamas%2C_Vernagt-Stausee%2C_Italy.jpg"
-      output: "llama"
-
-test_response_multi_turn_image:
-  test_name: test_response_multi_turn_image
-  test_params:
-    case:
-    - case_id: "llama_image_search"
-      turns:
-      - input:
-        - role: user
-          content:
-          - type: input_text
-            text: "What type of animal is in this image? Please respond with a single word that starts with the letter 'L'."
-          - type: input_image
-            image_url: "https://upload.wikimedia.org/wikipedia/commons/f/f7/Llamas%2C_Vernagt-Stausee%2C_Italy.jpg"
-        output: "llama"
-      - input: "Search the web using the search tool for the animal from the previous response. Your search query should be a single phrase that includes the animal's name and the words 'maverick' and 'scout'."
-        tools:
-        - type: web_search
-        output: "model"