Make Transformers Nightly tests soft-fail and enable all tests (#29401)

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

.buildkite/test-pipeline.yaml

@@ -903,11 +903,12 @@ steps:
 - label: Transformers Nightly Models Test
   working_dir: "/vllm-workspace/"
   optional: true
+  soft_fail: true
   commands:
     - pip install --upgrade git+https://github.com/huggingface/transformers
-    - pytest -v -s tests/models/test_initialization.py -k 'not (Ultravox or Phi4Multimodal or MiniCPMO or Lfm2Moe or RobertaForSequenceClassification or Ovis2_5 or DeepseekOCR or KimiVL)'
+    - pytest -v -s tests/models/test_initialization.py
     - pytest -v -s tests/models/test_transformers.py
-    # - pytest -v -s tests/models/multimodal/processing/
+    - pytest -v -s tests/models/multimodal/processing/
     - pytest -v -s tests/models/multimodal/test_mapping.py
     - python3 examples/offline_inference/basic/chat.py
     - python3 examples/offline_inference/vision_language.py --model-type qwen2_5_vl