Improve-mm-and-pooler-and-decoding-configs (#16789)

Signed-off-by: Harry Mellor <19981378+hmellor@users.noreply.github.com>

tests/entrypoints/openai/test_vision.py

@@ -35,7 +35,7 @@ def server():
         "--enforce-eager",
         "--trust-remote-code",
         "--limit-mm-per-prompt",
-        f"image={MAXIMUM_IMAGES}",
+        str({"image": MAXIMUM_IMAGES}),
     ]
 
     with RemoteOpenAIServer(MODEL_NAME, args) as remote_server: