[BugFix] Bagel img2img e2e: drop extra_body height/width (#3054)

Signed-off-by: NumberWan <wantszkin2003@gmail.com>

tests/e2e/online_serving/test_bagel_online.py

@@ -107,7 +107,7 @@ def test_bagel_text2img_online(omni_server, openai_client) -> None:
 @hardware_test(res={"cuda": "H100", "rocm": "MI325"})
 @pytest.mark.parametrize("omni_server", test_params, indirect=True)
 def test_bagel_img2img_online(omni_server, openai_client) -> None:
-    """Test Bagel img2img with explicit height/width in chat completions API."""
+    """Test Bagel img2img via OpenAI-compatible chat completions API."""
     input_image = ImageAsset("2560px-Gfp-wisconsin-madison-the-nature-boardwalk").pil_image.convert("RGB")
     buffer = BytesIO()
     input_image.save(buffer, format="JPEG")
@@ -118,8 +118,6 @@ def test_bagel_img2img_online(omni_server, openai_client) -> None:
         "messages": _build_img2img_messages(IMG2IMG_PROMPT, image_b64),
         "modalities": ["image"],
         "extra_body": {
-            "height": 512,
-            "width": 512,
             "num_inference_steps": 2,
             "guidance_scale": 0.0,
             "seed": 42,