Fix Phi3 test that fails with Transformers v5 (#37298)

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

tests/models/multimodal/pooling/test_phi3v.py

@@ -3,6 +3,7 @@
 
 import pytest
 import torch.nn.functional as F
+import transformers.utils
 from PIL import Image
 
 from vllm.assets.base import get_vllm_public_assets
@@ -12,6 +13,12 @@ from ....conftest import IMAGE_ASSETS, HfRunner, PromptImageInput, VllmRunner
 from ....utils import large_gpu_test
 from ...utils import check_embeddings_close
 
+# BC for method that was deleted in Transformers v5.
+# Only needed for generating the HF reference.
+transformers.utils.is_flash_attn_greater_or_equal_2_10 = (
+    lambda: transformers.utils.is_flash_attn_greater_or_equal("2.1.0")
+)
+
 HF_TEXT_PROMPTS = [
     # T -> X
     "Find me an everyday image that matches the given caption: The label of the object is stop sign",  # noqa: E501