[Chore] Cleanup guided namespace, move to structured outputs config (#22772)

Signed-off-by: Aaron Pham <contact@aarnphm.xyz>
Signed-off-by: Harry Mellor <19981378+hmellor@users.noreply.github.com>
Co-authored-by: Harry Mellor <19981378+hmellor@users.noreply.github.com>

tests/v1/entrypoints/openai/test_chat_completion.py

@@ -77,7 +77,9 @@ async def test_invalid_json_schema(client: openai.AsyncOpenAI,
                 "role": "user",
                 "content": prompt,
             }],
-            extra_body={"guided_json": invalid_json_schema},
+            extra_body={"structured_outputs": {
+                "json": invalid_json_schema
+            }},
         )
 
 
@@ -99,7 +101,9 @@ async def test_invalid_regex(client: openai.AsyncOpenAI, model_name: str):
                 "content": prompt,
             }],
             extra_body={
-                "guided_regex": r"[.*",
+                "structured_outputs": {
+                    "regex": r"[.*"
+                },
                 "stop": ["\n"]
             },
         )
@@ -134,5 +138,9 @@ async def test_invalid_grammar(client: openai.AsyncOpenAI, model_name: str):
                 "role": "user",
                 "content": prompt,
             }],
-            extra_body={"guided_grammar": invalid_simplified_sql_grammar},
+            extra_body={
+                "structured_outputs": {
+                    "grammar": invalid_simplified_sql_grammar
+                }
+            },
         )